369 results on '"Lei Wang"'
Search Results
2. Hydrothermal carbonization of alfalfa: role of processing variables on hydrochar properties
- Author
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Jun Zhou, Mingjie Yu, Jianhua Qu, Modupe Sarah Akindolie, Fuxuan Bi, Yang Liu, Zhao Jiang, Lei Wang, Bo Zhang, and Ying Zhang
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Health, Toxicology and Mutagenesis ,Temperature ,Environmental Chemistry ,General Medicine ,Cellulose ,Pollution ,Carbon ,Medicago sativa - Abstract
Hydrothermal carbonization of alfalfa is a potential way to reuse agricultural waste. However, the effects of hydrothermal conditions on the properties of alfalfa-derived hydrochar are not clear. Herein, this study investigated the impact of different synthesis conditions (e.g., heating temperature, heating time, and solid to liquid ratio) on the formation and properties of hydrochar. Characterization and thermogravimetric analysis results revealed that with the increase of hydrothermal temperature and the extension of time, cellulose in alfalfa broken down more completely, and the number of carbon spheres and the aromatization degree increased, while the functional groups decreased. Furthermore, there was a surge in the carbon content, fixed carbon yield, high heating value, reduced oxygen, and volatile content. Additionally, the enhancement solid-liquid ratio could effectively improve the energy and mass yields. In all, by adjusting the process parameters of hydrochar, cleaner and higher productivity products could be obtained. This study provides theory basis for the production of target hydrochar that is used to soil amendments, adsorbents, and energy sources in the future.
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- 2022
3. Simulation of heavy metals behaviour during Co-processing of fly ash from municipal solid waste incineration with cement raw meal in a rotary kiln
- Author
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Lei, Wang, Xinyu, Huang, Xuantian, Li, Xiaotao, Bi, Dahai, Yan, Wenzheng, Hu, C, Jim Lim, and John R, Grace
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Lead ,Metals, Heavy ,Dust ,Particulate Matter ,Incineration ,Solid Waste ,Coal Ash ,Waste Management and Disposal ,Carbon ,Cadmium ,Refuse Disposal - Abstract
Fly ash produced from incineration of municipal solid wastes (MSW) contains heavy metals, such as Cd and Pb, that make this material difficult to manage and dispose of safely. Because the composition of fly ash is similar to cement raw meal, partial replacement of raw meal with fly ash may be a feasible way to reduce the health and environmental hazards of the ash, provided that the heavy metals can be effectively stabilized in the solid phase. This research employs proprietary thermochemical software to simulate the thermodynamic behavior and single-step fixation of Cd and Pb in industrial cement kilns. The effect of Cd, Pb and Cl loadings on the fixation and/or evaporation of Cd and Pb during the sintering process is analyzed using data from industrial cement kilns. A simplified model is created based on elemental mass balance to evaluate multi-step fixation of Cd and Pb with cement kiln dust recycle.The results indicate that Cd forms Cd(OH)
- Published
- 2022
4. ZnS anchored on porous N, S-codoped carbon as superior oxygen reduction reaction electrocatalysts for Al-air batteries
- Author
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Kun Xiang, Keke Zhi, Xiaomin Kang, Lei Wang, Jing-Li Luo, Xian-Zhu Fu, Linfang Cui, and Jiujun Zhang
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Battery (electricity) ,Materials science ,chemistry.chemical_element ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Gibbs free energy ,Catalysis ,Biomaterials ,Chemical kinetics ,symbols.namesake ,chemistry.chemical_compound ,Colloid and Surface Chemistry ,chemistry ,Chemical engineering ,Imidazolate ,symbols ,Reversible hydrogen electrode ,Carbon ,Pyrolysis - Abstract
The development of non-precious based oxygen reduction reaction (ORR) catalysts with outstanding catalytic performance is desirable but still a grand challenge for practical Al-air battery. Herein, we report a vulcanization-assisted pyrolysis strategy for creating zeolitic imidazolate framework-derived catalysts with a N, S co-doped carbon support and highly exposed ZnS and Zn-Nx sites. The trithiocyanuric acid (TCA) is found not only to introduce S into the carbon derived from ZIF-8 and ZnS to adjust the electronic structure of carbon matrix during the pyrolysis, but also result in a shrinkage of carbon framework with a hierarchical porous structure. Such an architecture boosts abundant active sites exposed and accelerates remote mass transportation. As a result, the optimized 3.5ZnS/NSC-NaCl-900 delivers an impressive enhanced performance toward ORR in alkaline medium with a high half-wave potential of 0.905 V (vs. reversible hydrogen electrode), which is superior to most of non-precious metal-based catalysts. Density functional theory calculations unveil that the ZnS in 3.5ZnS/NSC-NaCl-900 can effectively lower the Gibbs energy barrier of crucial steps and therefore promotes the reaction kinetics. Furthermore, 3.5ZnS/NSC-NaCl-900 also displays greater power density and specific capacity than Pt/C in Al-air batteries.
- Published
- 2022
5. Carbon dots derived from Poria cocos polysaccharide as an effective 'on-off' fluorescence sensor for chromium (VI) detection
- Author
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Qianqian Bao, Chengyuan Wu, Chen Weidong, Yunna Chen, Mengru Hu, Qianqian Huang, and Lei Wang
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Detection limit ,Quenching (fluorescence) ,Aqueous solution ,010401 analytical chemistry ,Pharmaceutical Science ,chemistry.chemical_element ,02 engineering and technology ,Pharmacy ,021001 nanoscience & nanotechnology ,01 natural sciences ,Fluorescence ,Hydrothermal circulation ,0104 chemical sciences ,Analytical Chemistry ,Chromium ,chemistry ,Nanosensor ,Drug Discovery ,Electrochemistry ,0210 nano-technology ,Carbon ,Spectroscopy ,Nuclear chemistry - Abstract
Chromium is a harmful contaminant showing mutagenicity and carcinogenicity. Therefore, detection of chromium requires the development of low-cost and high-sensitivity sensors. Herein, blue-fluorescent carbon quantum dots were synthesized by one-step hydrothermal method from alkali-soluble Poria cocos polysaccharide, which is green source, cheap and easy to obtain, and has no pharmacological activity due to low water solubility. These carbon quantum dots exhibit good fluorescence stability, water solubility, anti-interference and low cytotoxicity, and can be specifically combined with the detection of Cr(VI) to form a non-fluorescent complex that causes fluorescence quenching, so they can be used as a label-free nanosensor. High-sensitivity detection of Cr(VI) is achieved through internal filtering and static quenching effects. The fluorescence quenching degree of CDs fluorescent probe showed a good linear relationship with Cr(VI) concentration in the range of 1–100 μM. The linear equation was F0/F = 0.9942 + 0.01472[Cr(VI)] (R2 = 0.9922), and the detection limit can be as low as 0.25 μM (S/N = 3), which has been successfully applied to Cr(VI) detection in actual water samples herein.
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- 2022
6. A perspective on the electrocatalytic conversion of carbon dioxide to methanol with metallomacrocyclic catalysts
- Author
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Bing Ni, Xinyan Liu, Bo-Quan Li, Hong-Jie Peng, and Lei Wang
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Energy carrier ,Chemistry ,Commodity chemicals ,Energy Engineering and Power Technology ,chemistry.chemical_element ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Electrosynthesis ,01 natural sciences ,Combinatorial chemistry ,0104 chemical sciences ,Catalysis ,chemistry.chemical_compound ,Fuel Technology ,Electrochemistry ,Methanol ,0210 nano-technology ,Carbon ,Energy (miscellaneous) ,Electrochemical reduction of carbon dioxide ,Syngas - Abstract
Electrocatalytic carbon dioxide reduction (CO2R) presents a promising route to establish zero-emission carbon cycle and store intermittent renewable energy into chemical fuels for steady energy supply. Methanol is an ideal energy carrier as alternative fuels and one of the most important commodity chemicals. Nevertheless, methanol is currently mainly produced from fossil-based syngas, the production of which yields tremendous carbon emission globally. Direct CO2R towards methanol poses great potential to shift the paradigm of methanol production. In this perspective, we focus our discussions on producing methanol from electrochemical CO2R, using metallomacrocyclic molecules as the model catalysts. We discuss the motivation of having methanol as the sole CO2R product, the documented application of metallomacrocyclic catalysts for CO2R, and recent advance in catalyzing CO2 to methanol with cobalt phthalocyanine-based catalysts. We attempt to understand the key factors in determining the activity, selectivity, and stability of electrocatalytic CO2-to-methanol conversion, and to draw mechanistic insights from existing observations. Finally, we identify the challenges hindering methanol electrosynthesis directly from CO2 and some intriguing directions worthy of further investigation and exploration.
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- 2022
7. Low loading of P modified Rh nanoparticles encapsulated in N, P-doped carbon for boosted and pH-universal hydrogen evolution reaction
- Author
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Guishan Liu, Xuanyi Wang, Shaojin Chen, Junlu Bi, Jing-Qi Chi, Zhenyu Xiao, Xuejun Zhai, and Lei Wang
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Materials science ,Fabrication ,Electrolysis of water ,Renewable Energy, Sustainability and the Environment ,Energy Engineering and Power Technology ,chemistry.chemical_element ,Nanoparticle ,Heterojunction ,Overpotential ,Condensed Matter Physics ,Catalysis ,Fuel Technology ,chemistry ,Chemical engineering ,Carbon ,Pyrolysis - Abstract
Searching for highly efficient and Pt-free electrocatalysts with comparable hydrogen evolution reaction (HER) activities to the benchmark Pt/C catalyst is highly demanded for developing renewable water electrolysis system but still remains challenging. In the current work, low loading of P modified ultrafine Rh nanoparticles encapsulated in N, P dual-doped carbon layers (Rh–P@NPC) have been prepared through a facile polymerization-impregnation followed by high-temperature pyrolysis process. Benefiting from the unique core-shell structural advantages and synergistic effect of Rh–P and NPC components, the resulting Rh–P@NPC catalyst not only exhibits remarkable electrocatalytic activity for HER in the whole pH range with a low overpotential of 31 mV, 65 mV, and 130 mV to drive a current density of 10 mA cm−2 in 0.5 M H2SO4, 1.0 M KOH, and 1.0 M PBS, respectively, but also demonstrates high durability. It is worth to note that all these HER performances are on a par with commercial Pt/C catalysts for HER. This synthetic strategy provides possibility for the fabrication of carbon-based heterostructures with high catalytic activity and durability in harsh environments.
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- 2022
8. N, P-doped carbon supported ruthenium doped Rhenium phosphide with porous nanostructure for hydrogen evolution reaction using sustainable energies
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Yuxiao Gao, Lei Wang, Hongru Liu, Zexing Wu, Zhi Chen, Mingyu Shao, Ying Zhao, and Tianyi Ma
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Materials science ,Nanostructure ,Phosphide ,chemistry.chemical_element ,Electrocatalyst ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Catalysis ,Ruthenium ,Nanomaterials ,Biomaterials ,chemistry.chemical_compound ,Colloid and Surface Chemistry ,chemistry ,Chemical engineering ,Hydrogen fuel ,Carbon - Abstract
Developing efficient and cost-effective catalysts for hydrogen evolution reaction (HER) is vital to hydrogen energy's commercial applications. In this study, N,P-doped carbon supported ruthenium (Ru) doped triruthenium tetraphosphide (Re3P4) (Ru-Re3P4/NPC) with porous nanostructure is prepared using the low-toxic melamine phosphate as the carbon and phosphorous source. The in-situ generated N,P-doped carbon layers play a pivotal role in regulating the electrocatalytic activity by avoiding the aggregation of the nanoparticles and increasing the specific surface area. Moreover, Ru doping contributes to the remarkable electrocatalytic performance of the prepared nanomaterials. Impressively, the as-synthesized Ru-Re3P4/NPC presents remarkable electrocatalytic performances toward HER with small overpotentials of 39 mV, 115 mV, and 88 mV to deliver 10 mA cm−2 in alkaline, neutral, and acidic media. Moreover, the prepared electrocatalyst can drive water-splitting with a small potential of 1.45 V@10 mA cm−2 and use sustainable energies, including solar, wind, and thermal, as electric resources. This work paves a novel and valuable way to enhance the electrocatalytic performances of metal phosphides.
- Published
- 2022
9. Sol-gel pore-sealing strategy imparts tailored electronic structure to the atomically dispersed Ru sites for efficient oxygen reduction reaction
- Author
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Lingyu Feng, Lichen Zhang, Ming Zhou, Fenghong Lu, Xia Li, Kaicai Fan, Lixiu Cui, Lingbo Zong, Lei Wang, Bin Li, and Yanan Chen
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Battery (electricity) ,Materials science ,Renewable Energy, Sustainability and the Environment ,Energy Engineering and Power Technology ,chemistry.chemical_element ,Electronic structure ,Electrocatalyst ,Catalysis ,Metal ,chemistry ,Chemical engineering ,visual_art ,medicine ,visual_art.visual_art_medium ,General Materials Science ,Carbon ,Activated carbon ,medicine.drug ,Sol-gel - Abstract
Single-atom electrocatalysts (SACs) have demonstrated fascinated electrocatalytic performance towards oxygen reduction reaction (ORR), while designing SACs with abundant accessible active sites is still challenging. Here, we report a facile sol-gel pore-sealing strategy for anchoring N coordinated Ru single atoms (SAs) onto the pore edges of the activated carbon spheres (Ru-SAs@N-ACSs) to enhance their accessibility. The fabricated electrocatalyst possesses outstanding ORR performance under alkaline conditions, outperforming most of recently reported SACs. Theoretical calculations screen that carbon edge could significantly modify the second coordination spheres of the central Ru atoms and the electronic structures of Ru-N4 sites, contributing to preferable ORR intermediate adsorption energy and high intrinsic catalytic activity. The Zn–air battery assembled using Ru-SAs@N-ACSs exhibits high power density and remarkable charge–discharge stability. The projected strategy provides valuable guidance on fabricating highly accessible SAs and engineering the second coordination spheres of metal atoms to achieve efficient SACs.
- Published
- 2022
10. Initial-anode-free aluminum ion batteries: In-depth monitoring and mechanism studies
- Author
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Xinmei Song, Zuoxiu Tie, Yi Hu, Wen Yan, Lei Wang, and Zhong Jin
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Battery (electricity) ,Materials science ,Renewable Energy, Sustainability and the Environment ,Energy Engineering and Power Technology ,chemistry.chemical_element ,Nanotechnology ,Electrolyte ,Electrochemistry ,Cathode ,law.invention ,Anode ,chemistry ,law ,Plating ,General Materials Science ,Graphite ,Carbon - Abstract
Rechargeable aluminum-ion batteries have attracted great attention due to the high theoretical volumetric capacity, good safety and abundant sources. Although tremendous efforts have been concentrated on exploring novel electrode materials for aluminum-ion batteries, the electrochemical mechanism still need to be further investigated. In this work, we found that even without employing any initial anode materials, the aluminum-ion batteries assembled with graphite cathode, AlCl3/ion liquid based electrolyte and various anodic current collectors still can be stably charged/discharged. A variety of carbon or metal based materials can be utilized as anodic current collectors in the initial-anode-free aluminum-ion batteries; however, their anti-corrosion capabilities against Cl− ions do greatly affect the battery performances. The electrochemical mechanism of initial-anode-free aluminum-ion batteries were comprehensively investigated by a series of in-situ and ex-situ spectroscopic and microscopic methods, revealing the reversible Al metal plating/stripping processes on the anodic current collectors during the charge-discharge cycles. We hope this work may provide new insights into the key component design and mechanism study of initial-anode-free multivalent secondary batteries.
- Published
- 2022
11. Coordination engineering of cobalt phthalocyanine by functionalized carbon nanotube for efficient and highly stable carbon dioxide reduction at high current density
- Author
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Jianping Lai, Yue Pan, Yaodong Yu, Shouhua Feng, Zuochao Wang, Lei Wang, Haoyang Du, Juan Xiong, and Hongdong Li
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chemistry.chemical_element ,Monoxide ,Carbon nanotube ,Condensed Matter Physics ,Heterogeneous catalysis ,Atomic and Molecular Physics, and Optics ,law.invention ,Catalysis ,chemistry ,Chemical engineering ,law ,Desorption ,General Materials Science ,Electrical and Electronic Engineering ,Selectivity ,Carbon ,Electrochemical reduction of carbon dioxide - Abstract
Coordination engineering can enhance the activity and stability of the catalyst in heterogeneous catalysis. However, the axial coordination engineering between different groups on the carbon carrier and molecular catalysts in the electrocatalytic carbon dioxide reduction reaction (CO2RR) has been studied rarely. Through coordination engineering strategy, a series of amino (NH2), hydroxyl (OH), and carboxyl (COOH) groups functionalized carbon nanotubes (CNT) immobilized cobalt phthalocyanine (CoPc) catalysts are designed. Compared with no groups, OH groups and COOH groups, NH2 groups can effectively change the coordination environment of the central metal Co, thereby significantly increasing the turnover frequency (TOF) (31.4 s−1 at −0.6 V vs. RHE, CoPc/NH2-CNT > CoPc/OH-CNT > CoPc/COOH-CN > CoPc/CNT). In the flow cell, the CoPc/NH2-CNT catalyst has high carbon monoxide (CO) selectivity at high current density (∼ 100% at −225 mA·cm−2, ∼ 96% at −351 mA·cm−2). Importantly, the CoPc/NH2-CNT catalyst can operate stably for 100 h at 225 mA·cm−2. Theoretical calculations reveal that CoPc/NH2-CNT catalyst is beneficial to the formation of *COOH and desorption of *CO, thus promoting CO2RR. This work provides an excellent platform for understanding the effect of coordination engineering on electrocatalytic performance and promotes a way to explore efficient and stable catalysts in other applications.
- Published
- 2021
12. The highly dispersed Co-based nanoparticles encapsulated into porous N-doping carbon polyhedral with the low content of Ru modification as a promising cathode catalyst for long-life Li-O2 batteries
- Author
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Yueqin Yu, Yiru Ma, Huiqi Qu, Zhenzhen Chi, Ziyang Guo, Xiaoqiang Liu, and Lei Wang
- Subjects
Battery (electricity) ,Materials science ,Heteroatom ,Oxygen evolution ,Nanoparticle ,chemistry.chemical_element ,Condensed Matter Physics ,Atomic and Molecular Physics, and Optics ,Cathode ,law.invention ,Chemical engineering ,chemistry ,law ,General Materials Science ,Lithium ,Electrical and Electronic Engineering ,Pyrolysis ,Carbon - Abstract
Lithium (Li)-O2 batteries have triggered worldwide interest due to their ultrahigh theoretical energy density. However, it is a long shot for the grand-scale applications of Li-O2 battery at current stage owing to its significant polarization, inferior cycling life, and irreversible decomposition of Li2O2. Herein, a facile way of preparing the highly dispersed Co-based nanoparticles encapsulated into porous N-doping carbon polyhedral with the low content of Ru modification (LRu@HDCo-NC) is explored through the pyrolysis of Co/Zn based zeolitic imidazole frameworks (ZIFs) containing Ru-based ligands. Even with the very small amount of Ru introduction (1.8%), LRu@HDCo-NC still exhibits the superior oxygen evolution reaction/oxygen reduction reaction (OER/ORR) performance and also inhibits side reactions in Li-O2 battery because of the abundant pores, plentiful surface N heteroatoms, and highly dispersed metal-based sites which are induced by the volatilization of Zn, and conductive/stable carbon skeleton derived from ZIFs. When applied in Li-O2 batteries, LRu@HDCo-NC cathode delivers a high discharge capacity of 15,973 mAh·g−1 at 200 mA·g−1, good capacity retention at higher rate (12,362 mAh·g−1 at 500 mA·g−1) and outstanding stability for > 300 cycles with low voltage polarization of < 2.3 V under a cut-off capacity of 1,000 mAh·g−1 at 500 mA·g−1. More critically, a series of ex situ and in situ characterization technologies disclose that the LRu@HDCo-NC cathodes can effectively promote the reversible reactions in Li-O2 batteries.
- Published
- 2021
13. Properties and microstructures of a matrix graphite for fuel elements of pebble-bed reactors after hightemperature purification at different temperatures
- Author
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Zhou Xiangwen, Lei Wang, Zhang Jie, Yang Yang, Yaping Tang, Bing Liu, Zhenming Lu, and Kaihong Zhang
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Materials science ,Materials Science (miscellaneous) ,chemistry.chemical_element ,Microstructure ,Corrosion ,Catalysis ,Matrix (chemical analysis) ,Thermal conductivity ,chemistry ,Chemical engineering ,General Materials Science ,Graphite ,Pebble ,Carbon - Abstract
The matrix graphite (MG) of pebble fuel elements for a High Temperature Gas-cooled Reactor (HTGR), composed of 71wt% natural graphite, 18 wt% artificial graphite and 11 wt% phenolic resin-derived carbon, was purified by high temperature treatment (HTT), and its properties and microstructure were analyzed to investigate the effect of different HTT temperatures and optimize the purification temperature. Results showed that with increasing HTT temperature, its density and thermal conductivity gradually increased, but pore size and d002 gradually decreased. The rate of erosion caused by friction as the fuel pebbles move in the reactor also decreased. The ash content decreased significantly from to 18.2×10−6to 12.3×10−6 after HTT at 1600 °C, but changed little when the HTT temperature was further increased to 1900 °C, especially for catalytic metals such as Fe, Ni and Ca that are related to its corrosion rate. The microstructure improvement and ash content reduction at high temperatures jointly contributed to the increase in the anti-corrosion performance of MG. Based on properties such as crushing strength, erosion resistance, and corrosion rate, a HTT of 1600 °C is adequate although the MG gradually became more ordered with a further increase of HTT temperature from 1600 to 1900 °C. This determination of an appropriate HTT temperature for the production of MG for the fuel elements of an HTGR should improve the production efficiency and reduce the mass production cost of this material for a commercial HTGR.
- Published
- 2021
14. Molten salt assisted fabrication of Fe@FeSA-N-C oxygen electrocatalyst for high performance Zn-air battery
- Author
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Jian Zhao, Cheng Hao Chuang, Wenjun Zhang, Dongchen Qi, Kaicai Fan, Lingbo Zong, Porun Liu, and Lei Wang
- Subjects
Materials science ,Energy Engineering and Power Technology ,Nanoparticle ,chemistry.chemical_element ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Electrocatalyst ,01 natural sciences ,Exfoliation joint ,0104 chemical sciences ,Catalysis ,Fuel Technology ,Chemical engineering ,chemistry ,Electrochemistry ,Reversible hydrogen electrode ,Molten salt ,0210 nano-technology ,Platinum ,Carbon ,Energy (miscellaneous) - Abstract
Non-noble-metal-based electrocatalysts with superior oxygen reduction reaction (ORR) activity to platinum (Pt) are highly desirable but their fabrications are challenging and thus impeding their applications in metal-air batteries and fuel cells. Here, we report a facile molten salt assisted two-step pyrolysis strategy to construct carbon nanosheets matrix with uniformly dispersed Fe3N/Fe nanoparticles and abundant nitrogen-coordinated Fe single atom moieties (Fe@FeSA-N-C). Thermal exfoliation and etching effect of molten salt contribute to the formation of carbon nanosheets with high porosity, large surface area and abundant uniformly immobilized active sites. Aberration-corrected high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) image, X-ray absorption fine spectroscopy, and X-ray photoelectron spectroscopy indicate the generation of Fe (mainly Fe3N/Fe) and FeSA-N-C moieties, which account for the catalytic activity for ORR. Further study on modulating the crystal structure and composition of Fe3N/Fe nanoparticles reveals that proper chemical environment of Fe in Fe3N/Fe notably optimizes the ORR activity. Consequently, the presence of abundant FeSA-N-C moieties, and potential synergies of Fe3N/Fe nanoparticles and carbon shells, markedly promote the reaction kinetics. The as-developed Fe@FeSA-N-C-900 electrocatalyst displays superior ORR performance with a half-wave potential (E1/2) of 0.83 V versus reversible hydrogen electrode (RHE) and a diffusion limited current density of 5.6 mA cm−2. In addition, a rechargeable Zn-air battery device assembled by the Fe@FeSA-N-C-900 possesses remarkably stable performance with a small voltage gap without obvious voltage loss after 500 h of operation. The facile synthesis strategy for the high-performance composites represents another viable avenue to stable and low-cost electrocatalysts for ORR catalysis.
- Published
- 2021
15. Iron and boron-doped carbonized zeolitic imidazolate frameworks as efficient oxygen reduction electrocatalysts for Al-Air batteries
- Author
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Guodong Fu, Lei Wang, Xian-Zhu Fu, Fengzhan Si, Xiaohui Deng, Xiaomin Kang, and Jing-Li Luo
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Materials science ,Dopant ,Renewable Energy, Sustainability and the Environment ,Carbonization ,Energy Engineering and Power Technology ,chemistry.chemical_element ,Condensed Matter Physics ,Catalysis ,Fuel Technology ,chemistry ,Chemical engineering ,Boron ,Pyrolysis ,Carbon ,Zeolitic imidazolate framework ,Power density - Abstract
Porous boron-bearing Fe-nitrogen doped carbon electrocatalysts (Fe-BNC) are prepared by pyrolysis treatment of Fe/B co-doped zeolitic imidazolate frameworks (ZIFs). The as-obtained Fe-BNC catalysts with a high surface area (1300 m2 g−1) favor a 4-electron reduction pathway for efficient oxygen reduction reaction (ORR). The Fe-BNC catalysts demonstrate a half-wave potential of ∼0.85 V vs RHE comparable to that of Pt/C catalyst and high stability in 0.1 M KOH. The dopant of little boron and iron into nitrogen-doped carbon results in the high surface area, enhanced surface polarities, electronic properties and exposing more active sites to introduce a synergistic effect for enhanced ORR performance. Moreover, Fe-BNC electrocatalysts used as air cathode for Al-air batteries exhibit a high peak power density of 195.2 mw cm−2 and excellent stability even after discharging for 24 h at room temperature, revealing an excellent performance in application of metal-air batteries and other energy converting devices.
- Published
- 2021
16. A zero-carbon emission chemical method to remove gaseous formaldehyde at room temperature by a renewable aminooxy-functionalized graphene composite
- Author
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Jiayan Pu, Lei Wang, Jinhou Fang, Tao Chen, Aihua Li, Zhen Liu, Yanzhi Xia, Xiutong Wang, and Jingquan Liu
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Formaldehyde ,Materials Chemistry ,Metals and Alloys ,Ceramics and Composites ,Temperature ,Graphite ,General Chemistry ,Gases ,Catalysis ,Carbon ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials - Abstract
We prepared a composite of aminooxy bifunctional molecules with graphene, which can decompose 91 mg of HCHO by 1 g of bifunctional molecules at room temperature with the only byproduct of water. Moreover, the composite can be regenerated under acidic conditions and 83.5% capacity is retained after 10 cycles.
- Published
- 2022
17. N/S co-doped carbon nanosheet bundles as high-capacity anode for potassium-ion battery
- Author
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Jian Zhu, Hongli Deng, Xidong Duan, Xinghui Wang, Shengyang Li, Lei Wang, Jinhui Cao, Hanjiao Xu, Ling Fan, Bingan Lu, Tao Wang, and Jiang Zhong
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Materials science ,Intercalation (chemistry) ,Analytical chemistry ,chemistry.chemical_element ,Potassium-ion battery ,Condensed Matter Physics ,Electrochemistry ,Atomic and Molecular Physics, and Optics ,Anode ,Ion ,chemistry ,General Materials Science ,Electrical and Electronic Engineering ,Carbon ,Faraday efficiency ,Nanosheet - Abstract
Potassium-ion batteries (PIBs) are of academic and economic significance, but still limited by the lack of highly active electrode materials for de-/intercalation of large-radius K ions. Herein, an interconnected nitrogen/sulfur co-doped carbon nanosheep bundle (N/S-CSB) was proposed as the potassium ions storage material. The rich co-doping of nitrogen/sulfur of N/S-CNB with three-dimensional hierarchical bundled array structure yields distensible interlayer spaces to buffer the volume expansion during K+ insertion/extraction, offers more electrochemical active sites to obtain a high specific capacity, and provides efficient channels for fast ion/electron transports. Therefore, the N/S-CSB anode achieved high reversible specific capacity of 365 mAh/g obtained at 50 mA/g after 200 cycles with a coulombic efficiency (CE) close to 100%, high rate performance and long cycle stability. Moreover, the in-situ Raman spectra indicated outstanding reaction kinetics of as-prepared N/S-CSB anode.
- Published
- 2021
18. Boron-Doped and Carbon-Controlled Porous Si/C Anode for High-Performance Lithium-Ion Batteries
- Author
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Yun Hang Hu, Chunling Wang, Lei Li, Lei Wang, and Jie Deng
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Materials science ,Energy Engineering and Power Technology ,chemistry.chemical_element ,Ion ,Anode ,chemistry ,Chemical engineering ,Boron doping ,Materials Chemistry ,Electrochemistry ,Chemical Engineering (miscellaneous) ,Lithium ,Electrical and Electronic Engineering ,Porosity ,Carbon - Published
- 2021
19. Controlling the coordination environment of Co atoms derived from Co/ZIF-8 for boosting photocatalytic H2 evolution of CdS
- Author
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Chao Wang, Qingjie Ji, Jixiang Xu, and Lei Wang
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Materials science ,Kinetics ,chemistry.chemical_element ,02 engineering and technology ,Conductivity ,010402 general chemistry ,Photochemistry ,01 natural sciences ,law.invention ,Biomaterials ,Metal ,Electronegativity ,chemistry.chemical_compound ,Colloid and Surface Chemistry ,law ,Calcination ,Triphenylphosphine ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,chemistry ,visual_art ,visual_art.visual_art_medium ,Photocatalysis ,0210 nano-technology ,Carbon - Abstract
Regulating the coordination environment of metal–Nx species by replacing N with low electronegativity atoms is an approach of tuning the electrocatalytic performance of metal-based sites. However, such effects on the enhancement of photocatalytic H2 evolution over semiconductors are not discussed yet. Herein, we designed and prepared Co-based cocatalysts with controlled coordination environment via calcination Co/ZIF-8 loaded with triphenylphosphine followed by a sulfurization treatment. It was then used as cocatalyst to modify CdS. The effects of the coordination environment of Co atoms on the H2 evolution activity of CdS were discussed. The obtained Co was co-stabilized by N, P, and S atoms and embedded in graphitic carbon (denoted as Co-NxPS/C). Experimental results indicated that the Co-NxPS/C exhibited high activity in enhancing H2 evolution of CdS with a value of 1260 μmol after 5 h irradiation. The simultaneous replacement of N with P and S atoms in N-stabilized Co embedded in carbon could enhance light harvesting, accelerate the transfer of photogenerated electrons from CdS to carbon with increased electrons accumulation ability and conductivity, improve charge separation efficiency, and enhance proton reduction kinetics. It is believed that the results of this study could promote the development of other high performance MOF-derived atomically dispersed cocatalysts to increase photocatalytic H2 evolution.
- Published
- 2021
20. The ordered mesoporous carbon coated graphene as a high-performance broadband microwave absorbent
- Author
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Jianfeng Zhu, Yiyong Mai, Zhen Du, Renchao Che, Shuheng Zhu, Dan Hou, Luoxing Xiang, and Lei Wang
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Nanocomposite ,Materials science ,Carbonization ,Graphene ,Reflection loss ,chemistry.chemical_element ,Nanotechnology ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,law.invention ,chemistry ,law ,General Materials Science ,0210 nano-technology ,Mesoporous material ,Absorption (electromagnetic radiation) ,Carbon ,Microwave - Abstract
There has been a great challenge in developing highly efficient electromagnetic microwave absorbers with strong absorbility, wide effective absorbing bandwidth and lightweight to solve the increasingly severe electromagnetic pollution. Here, we unveil the great potential of highly ordered mesoporous carbon coated graphene composites in the application of microwave absorption. The ordered mesoporous carbon composites possess well-defined spherical mesopores that are uniformly distributed on graphene surfaces and with uniform diameters of ∼20 nm (graphene@mesoporous carbon, abbreviated as G/MC). This renders the nanocomposites with high BET surface areas of up to 316 m2 g−1. Impressively, the G/MC nanosheets carbonized at 900 °C (G/MC-900) exhibit an outstanding microwave absorbility, with a maximum reflection loss (RL) of −66.1 dB and an exceptionally broad effective absorbing bandwidth (EAB) of 8.2 GHz (RL
- Published
- 2021
21. Insight on the active sites of CoNi alloy embedded in N-doped carbon nanotubes for oxygen reduction reaction
- Author
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Ying Wang, Xu Liu, Miaomiao Tong, Chungui Tian, Honggang Fu, and Lei Wang
- Subjects
Prussian blue ,Materials science ,Alloy ,Nanoparticle ,chemistry.chemical_element ,02 engineering and technology ,Carbon nanotube ,engineering.material ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,law.invention ,Catalysis ,Electron transfer ,chemistry.chemical_compound ,Chemical engineering ,chemistry ,Transition metal ,law ,engineering ,General Materials Science ,0210 nano-technology ,Carbon - Abstract
Transition metal alloy electrocatalysts have sparked intense interest for their use in oxygen reduction reaction (ORR). However, there is almost no corresponding research on the alloy active sites. In this study, CoNi alloy nanoparticles embedded in bamboo-like N-doped carbon nanotubes (CoNi-NCTs) as catalysts constructed by a facile pyrolysis of Prussian blue analogs were investigated. The density functional theory calculation reveals that the oxygen molecules are more easily adsorbed on the Ni sites in these catalysts, while the Co sites favor the formation of OOH⋆ intermediates during ORR. In addition, the cooperation of the CoNi alloys with the N-doped carbon benefits electron transfer and promotes electrocatalytic activity. The optimized CoNi-NCT shows remarkable ORR catalytic activity with an half-wave potential (E1/2) of 0.83 V, an onset potential (Eonset) of 0.97 V, and superior durability, all of which surpass the commercial Pt/C catalysts. The assembled zinc-air battery delivers a small charge/discharge voltage gap of 0.86 V at 10 mA cm−2, a high-power density of 167 mW cm−2, and good stability (running stably over 900 cycles).
- Published
- 2021
22. Constructing macroporous C/Co composites with tunable interfacial polarization toward ultra-broadband microwave absorption
- Author
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Ying Lin, Du Zhen, Xiaoyu Bai, and Lei Wang
- Subjects
Materials science ,Carbonization ,Reflection loss ,Composite number ,chemistry.chemical_element ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Biomaterials ,Colloid and Surface Chemistry ,chemistry ,Composite material ,0210 nano-technology ,Porosity ,Absorption (electromagnetic radiation) ,Carbon ,Microwave ,BET theory - Abstract
A porous structure is usually designed to balance impedance matching and attenuation capability of carbon-based microwave absorber, which has been investigated to be an effective way to obtain high microwave absorbing performance, such as strong absorbing capacity and wide effective absorbing bandwidth. Hitherto, there is little known about the suitable value of surface area for such porous structure. In this paper, macroporous C/Co composites were successfully fabricated via in situ carbonization of ZIF-67@SiO2 precursors and subsequent removal of the SiO2 with diameter of ~60 nm, and the BET (Brunauer- Emmett-Teller) surface area is optimized by adding amount of SiO2. When the BET surface area is ~340 m2g−1, the obtained macroporous C/Co composite shows the best microwave absorbing performance, and the maximum (RL reflection loss) is −56.2 dB with ultra-wide EAB (effective absorbing bandwidth) of 9.0 GHz (9.0–18.0 GHz) at ultralow filler loading of only 10 wt%.
- Published
- 2021
23. Formation pathways, gas-solid partitioning, and reaction kinetics of PCDD/Fs associated with baghouse filters operated at high temperatures: A case study
- Author
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Xiaoqing Lin, Xiaoxiao Wang, Yuxuan Ying, Angjian Wu, Zhiliang Chen, Lei Wang, Hong Yu, Hao Zhang, Aizhong Ruan, Xiaodong Li, and Jianhua Yan
- Subjects
Environmental Engineering ,Polychlorinated Dibenzodioxins ,Hot Temperature ,Temperature ,Incineration ,Dibenzofurans, Polychlorinated ,Pollution ,Coal Ash ,Carbon ,Environmental Chemistry ,Gases ,Dibenzofurans ,Waste Management and Disposal ,Benzofurans - Abstract
The application of the 3T method during combustion (i.e., a Temperature850 °C, a residence Time2 s, and sufficient Turbulence) can lead to elevated operating temperature in the baghouse filter for the municipal solid waste incineration (MSWI) systems without sufficient heat exchange capacity, which is potentially detrimental to the emission control of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs). Herein, a field study focusing on the distribution and variation of PCDD/Fs in gaseous and solid phases in a baghouse filter with high operating temperature (225-230 °C) was carried out. The concentration of PCDD/Fs in gases at the outlet of the baghouse filter was around 1 order of magnitude higher than that in inlet gases (i.e., noticeable memory effect of PCDD/Fs), because of the significant PCDD/Fs formation in filter fly ash (primarily contributed by the precursor pathway) followed by PCDD/Fs desorption. In addition, the mechanisms and factors resulting in the memory effect of PCDD/Fs were identified based on a laboratory study that carefully investigated the formation and desorption of PCDD/Fs at potential operating temperatures of baghouse filters (i.e., 180, 200, and 225 °C). The temperature was identified as the key factor inducing the memory effect of PCDD/Fs, because: i) PCDD/Fs memory effect was not observed for baghouse filters with low operating temperatures of ~150 °C in previous studies; ii) both the formation and desorption of PCDD/Fs were noticeably favored by rising temperature from 180 to 225 °C; iii) increasing temperature appeared to facilitate the transformation from inorganic Cl to organic Cl and the conversion from aliphatic carbon to aromatic carbon or unsaturated hydrocarbons, both of which were favorable to PCDD/Fs formation; and iv) the release rate of PCDD/Fs from fly ash was exponentially dependent on temperature based on the modeling results of reaction kinetics.
- Published
- 2022
24. [Temporal and Spatial Variations in Black Carbon Aerosol in Different Atmospheric Background Stations in China from 2006 to 2020]
- Author
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Hong-Lei, Wang, Xue, Yan, Li-Juan, Shen, Jane, Liu, Tian-Liang, Zhao, Xiao-Bin, Guan, and De-Long, Zhao
- Subjects
Aerosols ,Air Pollutants ,China ,Soot ,Seasons ,Carbon ,Environmental Monitoring - Abstract
Black carbon (BC) aerosol emissions are complex and have important environmental and meteorological effects. In China, the temporal and spatial variations in BC in different atmospheric environmental conditions need to be fully understood. Based on the long-term observational BC data in seven atmospheric background stations in China from 2006 to 2020, combined with meteorological data, emission source data, enhanced vegetation index (EVI) data, and aerosol optical depth (AOD) data, we comprehensively analyzed the characteristics of temporal and spatial variations, long-term evolution, and influencing factors of BC in China. The results showed that the BC and AOD values of different atmospheric environments in China were quite different, and BC positively contributed to AOD. The spatial distribution was high in the east and low in the west owing to the differences in emission sources and meteorological conditions. The
- Published
- 2022
25. Over-Expression of Phosphoserine Aminotransferase-Encoding Gene (
- Author
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Lei, Wang, Shuiling, Li, Ling, Sun, Yana, Tong, Lin, Yang, Yerong, Zhu, and Yong, Wang
- Subjects
Nitrogen ,Arabidopsis ,Serine ,Araceae ,Starch ,Plants, Genetically Modified ,Carbon ,Transaminases - Abstract
It has been demonstrated that the phosphorylation pathway of L-serine (Ser) biosynthesis (PPSB) is very important in plant growth and development, but whether and how PPSB affects nitrogen metabolism and starch accumulation has not been fully elucidated. In this study, we took the energy plant duckweed (strain
- Published
- 2022
26. [Temporal Evolution and Source Appointment of Black Carbon Aerosol in Ordos During Summer and Autumn 2019]
- Author
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Xiang-Chen, Kong, Lian-Xia, Zhang, Cai-Yun, Zhang, Hong-Lei, Wang, Jing, Xu, and Jia-Feng, Zheng
- Subjects
Aerosols ,Air Pollutants ,Soot ,Environmental Pollutants ,Carbon ,Environmental Monitoring - Abstract
In this study, black carbon (BC) aerosols were continuously observed using a seven-channel aethalometer (AE-33) in Ordos from August 12 to October 4, 2019; using this data combined with article matter (PM), pollutant gas, and meteorological element data; a HYSPLIT model; and potential source contribution function (PSCF) and concentration-weighted trajectory (CWT) models, we analyzed the temporal evolution and potential source appointment and main influence areas of BC. The results showed that the average of
- Published
- 2022
27. Optimal Decisions in a Multi-Party Closed-Loop Supply Chain Considering Green Marketing and Carbon Tax Policy
- Author
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Shan Lyu, Yuyu Chen, and Lei Wang
- Subjects
Marketing ,Policy ,Health, Toxicology and Mutagenesis ,Public Health, Environmental and Occupational Health ,Commerce ,Recycling ,carbon tax policy ,green marketing ,closed-loop supply chain ,retailer-dominated ,Carbon - Abstract
Global warming and e-waste pollution are two major environmental pollution issues that have attracted widespread attention. The government has adopted various measures to reduce carbon emissions from businesses and to make manufacturers responsible for recycling e-waste. In the face of external pressures, more and more companies are implementing sustainable closed-loop supply chain (CLSC) management to reduce environmental pollution and achieve sustainable development. Therefore, it is essential to study the operational decisions of CLSC enterprises. This paper considers a sustainable CLSC consisting of two competing manufacturers and a dominant retailer. The government imposes a carbon tax on the retailer, and two manufacturers collect used products directly from their customers. We separately examine whether implementing green marketing by the retailer and the collaboration between the two manufacturers can improve their profits. By building decentralized CLSC mathematical models and applying game theory methods, we obtain that green marketing can increase profits for all CLSC members and improve return rates. The collaboration may yield higher total profits for two manufacturers than a decentralized solution, while the retailer’s profits may be lost under certain conditions. Finally, we perform several numerical analyses to find the relationship between unit carbon emission tax and social welfare and gain some managerial insights. The study gives key factors that CLSC companies should consider when making decisions to help them achieve sustainability and provides recommendations for the government to set a reasonable unit carbon tax.
- Published
- 2022
28. Decoupled temperature and pressure hydrothermal synthesis of carbon sub-micron spheres from cellulose
- Author
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Shijie Yu, Xinyue Dong, Peng Zhao, Zhicheng Luo, Zhuohua Sun, Xiaoxiao Yang, Qinghai Li, Lei Wang, Yanguo Zhang, Hui Zhou, and Inorganic Materials & Catalysis
- Subjects
Multidisciplinary ,Hot Temperature ,Temperature ,General Physics and Astronomy ,General Chemistry ,General Biochemistry, Genetics and Molecular Biology ,Carbon ,Soil ,SDG 12 – Verantwoordelijke consumptie en productie ,Carbon/chemistry ,SDG 7 - Affordable and Clean Energy ,Cellulose ,SDG 12 - Responsible Consumption and Production ,SDG 7 – Betaalbare en schone energie - Abstract
The temperature and pressure of the hydrothermal process occurring in a batch reactor are typically coupled. Herein, we develop a decoupled temperature and pressure hydrothermal system that can heat the cellulose at a constant pressure, thus lowering the degradation temperature of cellulose significantly and enabling the fast production of carbon sub-micron spheres. Carbon sub-micron spheres can be produced without any isothermal time, much faster compared to the conventional hydrothermal process. High-pressure water can help to cleave the hydrogen bonds in cellulose and facilitate dehydration reactions, thus promoting cellulose carbonization at low temperatures. A life cycle assessment based on a conceptual biorefinery design reveals that this technology leads to a substantial reduction in carbon emissions when hydrochar replacing fuel or used for soil amendment. Overall, the decoupled temperature and pressure hydrothermal treatment in this study provides a promising method to produce sustainable carbon materials from cellulose with a carbon-negative effect.
- Published
- 2022
29. One-step preparation of Fe/N co-doped porous biochar for chromium(VI) and bisphenol a decontamination in water: Insights to co-activation and adsorption mechanisms
- Author
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Jianhua Qu, Xiubo Zhang, Shiqi Liu, Xiaojuan Li, Shuyue Wang, Zihan Feng, Zhihuan Wu, Lei Wang, Zhao Jiang, and Ying Zhang
- Subjects
Chromium ,Environmental Engineering ,Renewable Energy, Sustainability and the Environment ,Water ,Bioengineering ,General Medicine ,Carbon ,Phenols ,Charcoal ,Adsorption ,Benzhydryl Compounds ,Waste Management and Disposal ,Porosity ,Decontamination ,Water Pollutants, Chemical - Abstract
Herein, magnetic nitrogen doped porous biochar (Fe/N-PBC) was prepared by mixing KHCO
- Published
- 2022
30. PCDD/Fs and heavy metals in the vicinity of landfill used for MSWI fly ash disposal: Pollutant distribution and environmental impact assessment
- Author
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Xiaoqing Lin, Yunfeng Ma, Tong Chen, Lei Wang, Masaki Takaoka, Shuping Pan, Hao Zhang, Angjian Wu, Xiaodong Li, and Jianhua Yan
- Subjects
Polychlorinated Dibenzodioxins ,Health, Toxicology and Mutagenesis ,Sodium ,Water ,General Medicine ,Incineration ,Dibenzofurans, Polychlorinated ,Toxicology ,Solid Waste ,Pollution ,Coal Ash ,Carbon ,Dimethyldithiocarbamate ,Soil ,Waste Disposal Facilities ,Metals, Heavy ,Environmental Pollutants ,Dibenzofurans ,Water Pollutants, Chemical ,Cadmium - Abstract
This study focused on the syngenetic control of polychlorinated-ρ-dibenzodioxins and dibenzofurans (PCDD/Fs) and heavy metals by field stabilization/solidification (S/S) treatment for municipal solid waste incineration fly ash (MSWIFA) and multi-step leachate treatment. Modified European Community Bureau of Reference (BCR) speciation analysis and risk assessment code (RAC) revealed the medium environment risk of Cd and Mn, indicating the necessity of S/S treatment for MSWIFA. S/S treatment significantly declined the mass/toxic concentrations of PCDD/Fs (i.e., from 7.21 to 4.25 μg/kg; from 0.32 to 0.20 μg I-TEQ/kg) and heavy metals in MSWIFA due to chemical fixation and dilution effect. The S/S mechanism of sodium dimethyldithiocarbamate (SDD) and cement was decreasing heavy metals in the mild acid-soluble fraction to reduce their mobility and bioavailability. Oxidation treatment of leachate reduced the PCDD/F concentration from 49.10 to 28.71 pg/L (i.e., from 1.60 to 0.98 pg I-TEQ/L) by suspension absorption or NaClO oxidation decomposition, whereas a so-called "memory effect" phenomena in the subsequent procedures (adsorption, press filtration, flocculating settling, slurry separation, and carbon filtration) increased it back to 38.60 pg/L (1.66 pg I-TEQ/L). Moreover, the multi-step leachate treatment also effectively reduced the concentrations of heavy metals to 1-4 orders of magnitude lower than the national emission standards. Furthermore, the PCDD/Fs and heavy metals in other multiple media (soil, landfill leachate, groundwater, and river water) and their spatial distribution characteristics site were also investigated. No evidence showed any influence of the landfill on the surrounding liquid media. The slightly higher concentration of PCDD/Fs in the soil samples was ascribed to other waste management processes (transportation and unloading) or other local source (hazardous incineration plant). Therefore, proper management of landfills and leachate has a negligible effect on the surrounding environment.
- Published
- 2022
31. Operando Cooperated Catalytic Mechanism of Atomically Dispersed Cu−N 4 and Zn−N 4 for Promoting Oxygen Reduction Reaction
- Author
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Fanfei Sun, Ying Xie, Ying Wang, Yuqi Yang, Honggang Fu, Miaomiao Tong, Lei Wang, and Chungui Tian
- Subjects
Materials science ,010405 organic chemistry ,Inorganic chemistry ,chemistry.chemical_element ,General Chemistry ,General Medicine ,010402 general chemistry ,Rate-determining step ,01 natural sciences ,Catalysis ,XANES ,0104 chemical sciences ,Active center ,chemistry ,Atom ,Cluster (physics) ,Dispersion (chemistry) ,Carbon - Abstract
Dual-metal single-atom catalysts exhibit superior performance for oxygen reduction reaction (ORR), however, the synergistic catalytic mechanism is not deeply understood. Herein, we report a dual-metal single-atom catalyst consisted of Cu-N4 and Zn-N4 on the N-doped carbon support (Cu/Zn-NC). It exhibits high-efficiency ORR activity with an Eonset of 0.98 V and an E1/2 of 0.83 V, excellent stability (no degradation after 10 000 cycles), surpassing state-of-the-art Pt/C and great mass of Pt-free single atom catalysts. Operando XANES demonstrates that the Cu-N4 as active center experiences the change from atomic dispersion to cluster with the cooperation of Zn-N4 during ORR process, and then turns to single atom state again after reaction. DFT calculation further indicates that the adjustment effect of Zn on the d-orbital electron distribution of Cu could benefit to the stretch and cleavage of O-O on Cu active center, speeding up the process of rate determining step of OOH*.
- Published
- 2021
32. Dual-Carbon Electrode-Based High-Energy-Density Potassium-Ion Hybrid Capacitor
- Author
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Shengyang Li, Hongli Deng, Lei Wang, Jiang Zhong, Yiliu Wang, Mongur Hossain, Yaya Wang, Chunyu Cui, Tao Wang, Hanjiao Xu, Ling Fan, Jinhui Cao, Xiuqi Li, Jian Zhu, Bingan Lu, Yingliang Cheng, and Meng Zhang
- Subjects
Materials science ,chemistry.chemical_element ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Electrochemistry ,01 natural sciences ,Redox ,Cathode ,0104 chemical sciences ,Ion ,law.invention ,Anode ,chemistry ,Chemical engineering ,law ,Electrode ,General Materials Science ,0210 nano-technology ,Carbon ,Current density - Abstract
Potassium-ion hybrid capacitors (KIHCs) have attracted growing attention due to the natural abundance and low cost of potassium. However, KIHCs are still limited by sluggish redox reaction kinetics in electrodes during the accommodation of large-sized K+. Herein, a starch-derived hierarchically porous nitrogen-doped carbon (SHPNC) anode and active carbon cathode were rationally designed for dual-carbon electrode-based KIHCs with high energy density. The hierarchical structure and rich doped nitrogen in the SHPNC anode result in a distensible interlayer space to buffer volume expansion during K+ insertion/extraction, offers more electrochemical active sites to achieve high specific capacity, and has highly efficient channels for fast ion/electron transports. The in situ Raman and ex situ TEM demonstrated a reversible electrochemical behavior of the SHPNC anode. Thus, the SHPNC anode delivers superior cycling stability and a high reversible capacity (310 mA h g-1 at 50 mA g-1). In particular, the KIHCs assembled by the SHPNC anode and commercial active carbon cathode can deliver a high energy density of 165 W h kg-1 at a current density of 50 mA g-1 and an ultra-long cycle life of 10,000 cycles at 1 A g-1 (calculated based on the total mass of the anode and cathode).
- Published
- 2021
33. Responses of soil phosphorus pools accompanied with carbon composition and microorganism changes to phosphorus-input reduction in paddy soils
- Author
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Lei Wang, Yu Wang, Guanglei Chen, Jiahui Yuan, Hao Chen, Shenqiang Wang, and Xu Zhao
- Subjects
Phosphorus ,Microorganism ,food and beverages ,Soil Science ,chemistry.chemical_element ,04 agricultural and veterinary sciences ,Soil carbon ,010501 environmental sciences ,01 natural sciences ,Animal science ,Human fertilization ,chemistry ,Microbial population biology ,040103 agronomy & agriculture ,Soil phosphorus ,0401 agriculture, forestry, and fisheries ,Composition (visual arts) ,Carbon ,0105 earth and related environmental sciences - Abstract
In rice-wheat rotation systems, changes in soil phosphorus (P) pools and microorganisms in rice-growing seasons have been studied; however, further investigations are required to test whether these indexes exhibit different responses in wheat-growing seasons. Additionally, such studies need to include potential variations in soil carbon (C) structure and microbial community composition. In this study, a long-term rice-wheat rotation P-input reduction experiment was conducted to observe the variations in soil P pools and C composition in the 7th wheat season and to investigate the responses of soil enzyme activity and microbial communities. Four P fertilization treatments were included in the experiment, i.e., P application for rice season only (PR), for wheat season only (PW), and for both rice and wheat seasons (PR+W) and no P application in either season (Pzero). Compared with PR+W treatment, Pzero treatment significantly decreased (P
- Published
- 2021
34. Multi-dimensional ZnO@MWCNTs assembly derived from MOF-5 heterojunction as highly efficient microwave absorber
- Author
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Xiao Li, Xiaohui Li, Jie Zhang, Lei Wang, Renchao Che, and Min Wang
- Subjects
Materials science ,Scattering ,business.industry ,Reflection loss ,chemistry.chemical_element ,Heterojunction ,02 engineering and technology ,General Chemistry ,Carbon nanotube ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,law.invention ,chemistry ,law ,Optoelectronics ,General Materials Science ,0210 nano-technology ,business ,Absorption (electromagnetic radiation) ,Carbon ,Electrical conductor ,Microwave - Abstract
Metal-organic framework (MOF) derivatives have been arousing great attention in microwave absorption (MA) applications because of the adaptable morphological and component variance. However, it is still a huge challenge to construct multi-dimensional assembly with special heterostructure based on MOF and conductive carbon materials for excellent MA performance. Here, we successfully synthesized the cube-like assembly of multi-walled carbon nanotubes (MWCNTs) and ZnO (ZnO@MWCNTs) with unique multi-dimensional architecture via controlling the pyrolysis time of MOF-5 wrapped by MWCNTs. The ZnO@MWCNTs-4h are composed of zero-dimensional ZnO nanoparticles, one-dimensional MWCNTs, and three-dimensional micro-scale porous carbon framework. These various dimensional components confined within the cube space lead to the strong reflection loss (RL) at different frequencies, thus resulting in exceptional MA performance. The ZnO@MWCNTs-4h can reach a RL peak of −34.4 dB at only 1.5 mm thickness. More importantly, the maximum RL can achieve −47.4 dB at 2.7 mm with a mass loading as low as 20%. The optimized MA performance can be ascribed to high-density polarized sites, tightly interwoven MWCNTs conductive network, and strong multiple scattering that all induced by the multi-dimensional structures and components. Therefore, novel ZnO@MWCNTs composites are promising as a lightweight and highly efficient microwave absorber.
- Published
- 2021
35. Tailoring polysulfide trapping and kinetics by engineering hollow carbon bubble nanoreactors for high-energy Li-S pouch cells
- Author
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Xin Li, Jin Hu, Xiaobin Hong, Shuangke Liu, Huigao Duan, Lei Wang, Guanhua Zhang, Xianan Zhang, Chunman Zheng, and Yujie Li
- Subjects
Battery (electricity) ,Materials science ,Carbon nanofoam ,chemistry.chemical_element ,02 engineering and technology ,Nanoreactor ,Electrolyte ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,Atomic and Molecular Physics, and Optics ,Cathode ,0104 chemical sciences ,law.invention ,chemistry.chemical_compound ,Chemical engineering ,chemistry ,Electrochemical reaction mechanism ,law ,General Materials Science ,Electrical and Electronic Engineering ,0210 nano-technology ,Carbon ,Polysulfide - Abstract
Despite great progress of lithium-sulfur (Li-S) battery performance at the laboratory-level, both key parameters and challenges at cell scales to achieve practical high energy density require high-sulfur-loading cathodes and lean electrolytes. Herein, a novel carbon foam integrated by hollow carbon bubble nanoreactors with ultrahigh pore volume of 6.9 cm3·g−1 is meticulously designed for ultrahigh sulfur content up to 96 wt.%. Tailoring polysulfide trapping and ion/electron transport kinetics during the charge-discharge process can be achieved by adjusting the wall thickness of hollow carbon bubbles. And a further in-depth understanding of electrochemical reaction mechanism for the cathode is impelled by the in-situ Raman spectroscopy. As a result, the as-prepared cathode delivers high specific capacitances of 1,269 and 695 mAh·g−1 at 0.1 and 5 C, respectively. Furthermore, Li-S pouch cells with high areal sulfur loading of 6.9 mg·cm−2 yield exceptional practical energy density of 382 Wh·kg−1 under lean electrolyte of 3.5 µL·mg−1, which demonstrates the great potential for realistic high-energy Li-S batteries.
- Published
- 2021
36. Waste Polyethylene terephthalate Derived Carbon Dots for Separable Production of 5-Hydroxymethylfurfural at Low Temperature
- Author
-
Yaoping Hu, Mingfu Li, Gao Zhijin, Lei Wang, and Jian Zhang
- Subjects
Ethanol ,010405 organic chemistry ,Chemistry ,Biomass ,chemistry.chemical_element ,Sulfuric acid ,General Chemistry ,010402 general chemistry ,01 natural sciences ,Catalysis ,0104 chemical sciences ,Solvent ,chemistry.chemical_compound ,Chemical engineering ,Yield (chemistry) ,Polyethylene terephthalate ,Carbon - Abstract
Waste Polyethylene terephthalate plastic bottles were used as precursors to fabricate carbon dots (CDs) via air oxidation and sulfuric acid hydrothermal treatment. Owing to the nano-size effect and abundant acidic groups, CDs allowed their application as a novel solid acid for quasi-homogeneous catalytic dehydration of fructose to 5-hydroxymethylfurfural (HMF). Under the optimal condition, an ultra-high yield of HMF was 97.4% along with 100% fructose conversion at low temperature of 50 °C when [BMIM]Cl/ethanol was used as solvent. The CDs catalyst also displayed a prominent recyclability and was used for six recycles without massive loss in catalytic activity. Furthermore, 98.6% of HMF could be obtained from final products. The findings provide a novel sustainable route using recyclable plastics to synthesize carbon dots with a superior catalytic performance for conversion of biomass to important bio-based platform chemicals.
- Published
- 2021
37. Antimony alloying electrode for high-performance sodium removal: how to use a battery material not stable in aqueous media for saline water remediation
- Author
-
Volker Presser, Lei Wang, Öznil Budak, Mesut Aslan, Stefanie Arnold, and Pattarachai Srimuk
- Subjects
Battery (electricity) ,Materials science ,Renewable Energy, Sustainability and the Environment ,Capacitive deionization ,chemistry.chemical_element ,Context (language use) ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Desalination ,0104 chemical sciences ,chemistry ,Chemical engineering ,Electrode ,Fast ion conductor ,medicine ,General Materials Science ,0210 nano-technology ,Carbon ,Activated carbon ,medicine.drug - Abstract
Capacitive deionization (CDI) is based on ion electrosorption and has emerged as a promising desalination technology, for example, to obtain drinking water from brackish water. As a next-generation technology, battery desalination uses faradaic processes and, thereby, enables higher desalination capacities and remediation of feed water with high molar strength such as seawater. However, the full use of a large capacity of charge transfer processes is limited by the voltage window of water and the need to use electrode materials non-reactive towards the water. Using our multi-channel bi-electrolyte cell, we now introduce for the first time an alloying electrode for sodium removal in the context of water desalination. Separated by a ceramic sodium superionic conductor (NASICON) membrane, the antimony/carbon composite electrode accomplished sodium removal while chlorine removal is enabled via ion electrosorption with nanoporous carbon (activated carbon cloth). In a sodium-ion battery half-cell setup, the antimony/carbon composite electrode reaches an initial capacity of 714 mA h g−1 at a specific current of 200 mA g−1, which shows a slow but continuous degrading over the course of 80 cycles (426 mA h g−1 in 80th cycle). Our hybrid CDI cell provides a desalination capacity of an average of 294 mgNa gSb−1 (748 mgNaCl gSb−1) with a charge efficiency of ca. 74% in a 600 mM NaCl at a specific current of 200 mA g−1 and a voltage range of −2.0 V to +2.0 V.
- Published
- 2021
38. Accurate engineering of hexagonal hollow carbon nitride with carbon vacancies: enhanced photocatalytic H2 evolution and its mechanism
- Author
-
Qianqian Liu, Jing Ding, Xin Li, Lei Wang, Xueru Chen, Hongping Li, Hui Wan, Huimin Lu, Guofeng Guan, and Xue Li
- Subjects
Materials science ,Renewable Energy, Sustainability and the Environment ,chemistry.chemical_element ,General Chemistry ,Substrate (electronics) ,chemistry.chemical_compound ,Adsorption ,chemistry ,Chemical engineering ,Etching (microfabrication) ,Vacancy defect ,Photocatalysis ,Molecule ,General Materials Science ,Carbon nitride ,Carbon - Abstract
Vacancy engineering and morphology construction were integrated simultaneously by the self-assembly of melamine (MA) and cyanuric acid (CA) in the presence of P123 and H2SO4, which contributed to the hexagonal hollow carbon nitride with carbon vacancies (HHCN). P123 functioned as the structure directing agent and H2SO4 acted as the hole-maker and stability-maintainer, the synergistic effect of whom contributed to the hexagonal hollow structure. Meanwhile, the chemical oxidation etching of H2SO4 brought about carbon vacancies. Combined with experiments and DFT calculations, it was found that carbon vacancy improved the separation rate of photo-induced carriers as well as the adsorption capacity of reaction substrate (H2O molecules) and negatively shifted the CB potential. Therefore, HHCN was endowed with the superior photocatalytic hydrogen evolution rate (5140 μmol h−1 g−1), which was 18.3-fold higher than g-C3N4. Furthermore, the possible formation mechanism and photocatalytic mechanism were proposed. This work offered an excellent basis for vacancy engineering and morphology construction for the modification of carbon nitride.
- Published
- 2021
39. Iridium coated Co nanoparticles embedded into highly porous N-doped carbon nanocubes grafted with carbon nanotubes as a catalytic cathode for high-performance Li–O2 batteries
- Author
-
Qian Zhang, Huixiang Yin, Jie Liu, Dongdong Li, Xiaoqiang Liu, Lei Wang, Ling Ding, Ziyang Guo, Zhenzhen Chi, and Shaoxiang Li
- Subjects
Materials science ,Renewable Energy, Sustainability and the Environment ,Carbonization ,Nanoparticle ,chemistry.chemical_element ,General Chemistry ,Carbon nanotube ,Overpotential ,Cathode ,Catalysis ,law.invention ,chemistry ,Chemical engineering ,law ,General Materials Science ,Carbon ,Zeolitic imidazolate framework - Abstract
Rechargeable Li–O2 batteries have attracted worldwide attention due to their super-high energy density. However, there are still many critical challenges for Li–O2 batteries, such as huge overpotential caused by sluggish oxygen reduction/evolution reaction (ORR/OER) kinetics, and inferior cycle life derived from severe side reactions. Designing highly efficient cathode catalysts should be a good choice for Li–O2 batteries to solve the above problems. Herein, we developed Ir-coated Co nanoparticles confined into highly porous N-doped carbon nanocubes grafted with carbon nanotubes (Ir–Co/HP-NC/CNT) through carbonization of the Co/Zn–zeolitic imidazolate framework (ZIF) and the subsequent Ir-coating. Introduction of Zn into the ZIF precursor not only makes Ir–Co/HP-NC/CNT have high porosity that can promote ion/electron transfer, but also improves the surface content of pyridinic/graphitic N and CoxN phases which accelerate ORR/OER kinetics. Moreover, theoretical calculation/experimental results further confirm that the synergy between the Ir-coating and Co/HP-NC/CNT can effectively alleviate undesired parasitic reactions and also enhance reversibility in Li–O2 batteries by adjusting Li2O2 formation. As a result, Ir–Co/HP-NC/CNT based Li–O2 batteries show a super-high discharge capacity of 13 200 mA h g−1 at 100 mA g−1 and a very long cycling life up to 320 cycles at 500 mA g−1 with a fixed capacity of 1000 mA h g−1. Importantly, we have also designed large-size bulk-shaped Li–air batteries with Ir–Co/HP-NC/CNT cathodes that exhibit good performance even under bending conditions and effectively power practical electronic devices.
- Published
- 2021
40. K+, Ni and carbon co-modification promoted two-electron O2 reduction for photocatalytic H2O2 production by crystalline carbon nitride
- Author
-
Xuemei Yan, Jixiang Xu, Lei Wang, and Yanfang Chen
- Subjects
Materials science ,Dopant ,Renewable Energy, Sustainability and the Environment ,Orbital hybridisation ,chemistry.chemical_element ,General Chemistry ,Crystallinity ,chemistry.chemical_compound ,Nanocrystal ,chemistry ,Chemical engineering ,Yield (chemistry) ,Photocatalysis ,General Materials Science ,Carbon nitride ,Carbon - Abstract
H2O2 has a wide range of uses as an oxidant and is also utilized as a high density and environmentally friendly fuel. In this study, crystalline g-C3N4 was modified with K+, Ni and N-doped carbon by thermal-polymerization of Ni2+-anchored and polyvinyl pyrrolidone-encapsulated melamine-cyanuric acid supramolecules, followed by re-calcination in a KCl–LiCl mixture. The obtained strip-like g-C3N4 nanocrystals exhibited high charge separation efficiency and good light absorption capability. Density-functional theory calculations confirmed that the orbital hybridization of Ni–N atoms enabled the formation of charge-transfer channels, which can capture electrons, achieve enhanced oxygen adsorption and reduction via a two-electron pathway. Under the synergistic effects of K+, Ni and N-doped carbon dopants and crystallinity, the obtained sample exhibited high photocatalytic H2O2 yields of 79.6 μM in O2-saturated pure water, which was 10-fold higher than the yield using pristine g-C3N4. This work provides a novel design for production of highly efficient photocatalysts for H2O2 production.
- Published
- 2021
41. Structural Evaluation of Coal Tar Pitch by Multiple Techniques
- Author
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Jun Shen, Zhi-Lei Wang, Yan-Xia Niu, Yu-Gao Wang, Ze-Shi Niu, and Wei Zhao
- Subjects
010405 organic chemistry ,General Chemical Engineering ,Energy Engineering and Power Technology ,chemistry.chemical_element ,Aromaticity ,General Chemistry ,010402 general chemistry ,01 natural sciences ,Sulfur ,0104 chemical sciences ,law.invention ,Crystallography ,Fuel Technology ,chemistry ,Geochemistry and Petrology ,law ,Side chain ,medicine ,Cluster (physics) ,Coal tar ,Carbon ,Distillation ,Diffractometer ,medicine.drug - Abstract
Coal tar pitch (CTP) is an important heavy carbon resource. Its effective utilization largely depends on the full structural evaluation of CTP. In this paper, the CTP from Shanxi Datuhe coal tar distillation plant was adopted as the sample (DCTP). Multiple analytical equipments including X-ray diffractometer spectrometer, solid-state 13C nuclear magnetic resonance spectrometer, and X-ray photoelectron spectrometer were used to directly characterize DCTP, and DCTP was further catalytically oxidized over ruthenium ion. The typical characteristics of structures in DCTP were investigated by combining the two methods. It was demonstrated that aromatic structures dominated in DCTP, in which the aromaticity was up to 95 %. Specifically, aromatic structures were abundant in peri-condensed aromatic structures, poor in cata-condensed aromatic structures, but short of polyaryl structures. There were about 4 rings in each aromatic cluster, and the aromatic clusters were lowly substituted by a few methyl side chains. Furthermore, the nitrogen and sulfur atoms mainly existed in the heterocyclic ring, while the oxygen one was principally in Car‒O group.
- Published
- 2020
42. Core-shell-structured Co@Co4N nanoparticles encapsulated into MnO-modified porous N-doping carbon nanocubes as bifunctional catalysts for rechargeable Zn–air batteries
- Author
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Bin Li, Yuanyuan Cui, Huimin Zhao, Yiru Ma, Lei Wang, Ziyang Guo, Fengmei Wang, and Yu Yang
- Subjects
Battery (electricity) ,Materials science ,Energy Engineering and Power Technology ,chemistry.chemical_element ,Nanoparticle ,02 engineering and technology ,Overpotential ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Electrochemistry ,01 natural sciences ,0104 chemical sciences ,Catalysis ,chemistry.chemical_compound ,Fuel Technology ,chemistry ,Chemical engineering ,0210 nano-technology ,Bifunctional ,Carbon ,Bimetallic strip ,Energy (miscellaneous) - Abstract
Designing the highly catalytic activity and durable bifunctional catalysts toward oxygen reduction/evolution reaction (ORR/OER) is paramount for metal–air batteries. Metal–organic frameworks (MOFs)-based materials have attracted a great deal of attention as the potential candidate for effectively catalyzing ORR/OER due to their adjustable composition and porous structure. Herein, we first introduce the Mn species into zeolitic-imidazole frameworks (ZIFs) and then further pyrolyze the Mn-containing bimetallic ZIFs to synthesize core-shell-structured Co@Co4N nanoparticles embedded into MnO-modified porous N-doped carbon nanocubes (Co@Co4N/MnO NC). Co@Co4N/MnO NC exhibits the outstanding catalytic activity toward ORR and OER which is attributed to its abundant pyridinic/graphitic N and Co4N, the optimized content of MnO species, highly dispersed catalytic sites and porous carbon matrix. As a result, the Co@Co4N/MnO NC-based Zn–air battery exhibits enhanced performances, including the high discharge capacity (762 mAh gZn−1), large power density (200.5 mW cm−2), stable potential profile over 72 h, low overpotential ( NC cathode-based Zn–air batteries are also designed which exhibit the superb electrochemical properties at different bending/twisting conditions.
- Published
- 2020
43. High-Temperature Synthesis of Small-Sized Pt/Nb Alloy Catalysts on Carbon Supports for Hydrothermal Reactions
- Author
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Weixin Huang, Hai-Wei Liang, Ping Chen, Lei Wang, Lu-Jie Zuo, Shuai Zhao, Shi-Long Xu, Wei Xiong, Shan-Cheng Shen, Kun Qian, Shengqi Chu, Wei-Jie Zeng, and Yue Lin
- Subjects
010405 organic chemistry ,Alloy ,chemistry.chemical_element ,Sintering ,Carbon black ,engineering.material ,010402 general chemistry ,01 natural sciences ,Hydrothermal circulation ,Water-gas shift reaction ,0104 chemical sciences ,Catalysis ,Inorganic Chemistry ,chemistry.chemical_compound ,chemistry ,Chemical engineering ,Levulinic acid ,engineering ,Physical and Theoretical Chemistry ,Carbon - Abstract
Catalytic biomass conversions are sustainable processes to produce value-added fuels and chemicals but need stable catalysts that can tolerate harsh hydrothermal conditions. Herein, we report a hydrothermally stable catalyst by alloying Pt with a high-melting-point metal Nb. The Pt/Nb alloy catalysts are prepared by H2 reduction at a high temperature of 900 °C with a high-surface-area carbon black support, which can suppress metal sintering at high temperatures and thus lead to small-sized alloyed Pt/Nb particles of only 2.2 nm. Taking the advantages of surface acid property provided by the Nb sites and the size effect, the prepared C-supported small-sized Pt/Nb alloy catalysts exhibit attractive activities for the hydrogenation of levulinic acid into γ-valerolactone and the water-gas shift reaction. More significantly, benefiting from the inherent stability of high-melting-point Nb, the Pt/Nb alloy catalysts show much enhanced hydrothermal stability compared to commercial Pt/C and Ru/C catalysts.
- Published
- 2020
44. Enzymatic preparation of rice-starch-based surface-modified disordered carbon as an anode for lithium-ion batteries
- Author
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Shidi Lai, Huishi Guo, Yinlong Lai, Ping Liu, Lejie Zhu, Zhipeng Sun, Jianmin Luo, and Lei Wang
- Subjects
Materials science ,General Chemical Engineering ,General Engineering ,food and beverages ,General Physics and Astronomy ,chemistry.chemical_element ,02 engineering and technology ,Electrolyte ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Electrochemistry ,01 natural sciences ,0104 chemical sciences ,Anode ,chemistry ,Chemical engineering ,Electrode ,Surface modification ,General Materials Science ,Lithium ,0210 nano-technology ,Carbon ,Faraday efficiency - Abstract
A unique surface-modified rice-starch-based disordered carbon (SRC) was prepared with the intention of improving the electrochemical properties of anodes for Li-ion batteries. The starch’s surface was altered via an enzymatic hydrolysis process, and these changes were retained following a heat treatment process to create a porous surface. Following surface modification, SRC-based anodes exhibited a higher reversible capacity and coulombic efficiency in the first cycle at the same current density when compared with unmodified rice-starch-based disordered carbon (RC). SRC-based electrodes also displayed improved rate capability behavior and cycling performance. Across the measurements performed during this body of work, the electrodes’ performances were improved when (i) the contact area between the SRC particles and the electrolyte was maximized and (ii) the ordering of the particles on the surface was improved. These results indicate that this is a viable approach for the creation of anodes for Li-ion batteries from modified biomass sources.
- Published
- 2020
45. Nitrogen-fixing of ultrasmall Pd-based bimetallic nanoclusters on carbon supports
- Author
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Hai-Wei Liang, Peng Yin, Shi-Long Xu, Lei Wang, Ping Chen, Le-Le Zhang, and Shan-Cheng Shen
- Subjects
010405 organic chemistry ,chemistry.chemical_element ,010402 general chemistry ,Heterogeneous catalysis ,01 natural sciences ,Catalysis ,0104 chemical sciences ,Styrene ,Nanoclusters ,chemistry.chemical_compound ,chemistry ,Chemical engineering ,Electronic effect ,Physical and Theoretical Chemistry ,Bimetallic strip ,Carbon - Abstract
Synthesis of supported Pd-based bimetallic catalysts is of great importance in the heterogeneous catalysis field owing to their optimal geometric and electronic effects. Downsizing active metals to ultrasmall nanocluster ( 93% to styrene, demonstrating the alloying and small-size effects in the bimetallic nanocluster catalysts.
- Published
- 2020
46. Sedimentary organic carbon storage of thermokarst lakes and ponds across Tibetan permafrost region
- Author
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Zhiqiang Wei, Zhiheng Du, Lei Wang, Wei Zhong, Jiahui Lin, Qian Xu, and Cunde Xiao
- Subjects
Lakes ,Soil ,Environmental Engineering ,Environmental Chemistry ,Permafrost ,Ponds ,Tibet ,Pollution ,Waste Management and Disposal ,Carbon - Abstract
Sedimentary soil organic carbon (SOC) stored in thermokarst lakes and ponds (hereafter referred to as thaw lakes) across high-latitude/altitude permafrost areas is of global significance due to increasing thaw lake numbers and their high C vulnerability under climate warming. However, to date, little is known about the SOC storage in these lakes, which limits our better understanding of the fate of these active carbon in a warming future. Here, by combining large-scale field observation data and published deep (e.g., 0-300 cm) permafrost SOC data with a random forest (RF) machine learning technique, we provided the first comprehensive estimation of thaw lake SOC stocks to 3 m depth on the Tibetan Plateau. This study demonstrated that combining multiple environmental factors with the RF model could effectively predict the spatial distributions of the thaw lake SOC density values (SOCDs). The model results revealed that the soil respiration, normalized difference vegetation index (NDVI), and mean annual precipitation (MAP) were the most influential factors for predicting thaw lake SOCDs. In total, the sedimentary SOC stocks in the thaw lakes were approximately 52.62 Tg in the top 3 m, with 53% of the SOC stored in the upper layers (0-100 cm). The SOCDs generally exhibited high values in eastern Tibetan Plateau, and low values in mid- and western Tibetan Plateau, which were similar to the patterns of the land cover types that affected the SOCDs. We further found that the SOCDs of thaw lakes were generally higher than those of their surrounding permafrost soils at different layer depths, which could be ascribed to the erosion of soil particles or leaching solution from the thawing permafrost soils to lakes and/or enhanced vegetation growth at the lake bottom. This research highlights the necessity of explicitly considering the thaw lake SOC stocks in Earth system models for more comprehensive future projections of the carbon dynamics on the plateau.
- Published
- 2022
47. Optimization of plant harvest and management patterns to enhance the carbon sink of reclaimed wetland in the Yangtze River estuary
- Author
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Wenxuan Mei, Qiuxiao Yin, Xiaoping Tian, Xiaohua Fu, Yongjian Guan, and Lei Wang
- Subjects
Carbon Sequestration ,China ,Soil ,Environmental Engineering ,Rivers ,Wetlands ,Humans ,General Medicine ,Management, Monitoring, Policy and Law ,Plants ,Estuaries ,Waste Management and Disposal ,Carbon - Abstract
Estuarine wetlands are often located in economically developed and densely populated estuarine deltas, which are frequently disturbed and threatened by human activities. Reclamation, as an important way to alleviate the demand for local land resources, can lead to habitat destruction of natural coastal wetlands and weakening of ecological service functions, including carbon sink capacity. Research has shown that poor plant growth and weakened carbon fixation were the main reasons for the reduced carbon sequestration in a reclaimed wetland. This study aimed to examine the impacts of plant management on the improvement or restoration of carbon sink function in Chongming Dongtan reclaimed wetland, located in the Yangtze River Estuary, China. A management pattern that could effectively enhance the carbon sink function of the reclaimed wetland was selected based on analyses of the effects of different plant harvesting and management patterns (no harvesting, harvesting without returning to the field, direct straw return, and charred straw return) on the plant growth, carbon fixation, and soil respiration, combined with whole-life-cycle carbon footprint evaluation from straw harvest to field return. Compared with no harvesting, the aboveground biomass of direct straw return and charred straw return increased by about 12.3% and 15.5%, respectively (P 0.05). Simultaneously, straw charring released the least amount of CO
- Published
- 2022
48. Regulating Capacitive Performance of Monolithic Carbon Sponges by Balancing Heteroatom Content, Surface Area and Graphitization Degree
- Author
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Wenjun Kang, Lei Wang, Xiangxia Jing, Rui Li, Zengjing Guo, Lan Zhou, Konggang Qu, Denghu Wei, Haibo Li, and Baoli Chen
- Subjects
Supercapacitor ,Surface (mathematics) ,Materials science ,Renewable Energy, Sustainability and the Environment ,Capacitive sensing ,Heteroatom ,Energy Engineering and Power Technology ,chemistry.chemical_element ,Degree (temperature) ,Biomaterials ,Chemical engineering ,chemistry ,Materials Chemistry ,Carbon - Published
- 2020
49. A library of carbon-supported ultrasmall bimetallic nanoparticles
- Author
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Shan-Cheng Shen, Shuai Zhao, Lu-Jie Zuo, Ming-Xi Chen, Ping Chen, Yue Lin, Zeyue Wei, Yanwei Ding, Lei Wang, Kun Qian, Hai-Wei Liang, Shengqi Chu, and Shi-Long Xu
- Subjects
Materials science ,chemistry.chemical_element ,Nanoparticle ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,Atomic and Molecular Physics, and Optics ,0104 chemical sciences ,Catalysis ,Metal ,Chemical engineering ,chemistry ,visual_art ,visual_art.visual_art_medium ,Particle ,General Materials Science ,Dehydrogenation ,Electrical and Electronic Engineering ,0210 nano-technology ,Mesoporous material ,Carbon ,Bimetallic strip - Abstract
Small-sized bimetallic nanoparticles that possess numerous accessible metal sites and optimal geometric/electronic structures show great promise for advanced synergetic catalysis but remain synthetic challenge so far. Here, an universial synthetic method is developed for building a library of bimetallic nanoparticles on mesoporous sulfur-doped carbon supports, consisting of 24 combinations of 3 noble metals (that is, Pt, Rh, Ir) and 7 other metals, with average particle sizes ranging from 0.7 to 1.4 nm. The synthetic strategy is based on the strong metal-support interaction arising from the metal-sulfur bonding, which suppresses the metal aggregation during the H2-reduction at 700 °C and ensure the formation of small-sized and alloyed bimetallic nanoparticles. The enhanced catalytic properties of the ultrasmall bimetallic nanoparticles are demonstrated in the dehydrogenation of propane at high temperature and oxidative dehydrogenations of N-heterocycles.
- Published
- 2020
50. Comparative life cycle assessment of two ceramsite production technologies for reusing municipal solid waste incinerator fly ash in China
- Author
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Hailong Zhao, Han-Qiao Liu, Ying Hao, Rui Zhang, Lei Wang, and Fang Liu
- Subjects
China ,Polychlorinated Dibenzodioxins ,020209 energy ,Incineration ,02 engineering and technology ,010501 environmental sciences ,Reuse ,Solid Waste ,Coal Ash ,01 natural sciences ,law.invention ,Municipal solid waste incinerator ,Comparative life cycle assessment ,law ,Metals, Heavy ,0202 electrical engineering, electronic engineering, information engineering ,Production (economics) ,Waste Management and Disposal ,Life-cycle assessment ,Rotary kiln ,0105 earth and related environmental sciences ,Waste management ,Carbon ,Refuse Disposal ,Fly ash ,Environmental science ,Particulate Matter ,Dibenzofurans - Abstract
Harmless treatment and reuse of municipal solid waste incinerator fly ash are challenging. Two reuse technologies of converting incinerator fly ash to ceramsites via rotary kiln sintering and non-sintering have been demonstrated in China. Field monitoring results reveal that the destruction efficiency of PCDD/Fs are both higher than 99% in two processes. The leaching rate of heavy metals in both ceramsite products, their pollutant emissions in production process meet the standards. Environmental impacts of two ceramsite products were compared using life cycle assessment approach. Rotary kiln sintering ceramsite has lower environmental impacts in most categories and delivers a smaller integrated impacts index than non-sintering ceramsite. For rotary kiln sintering ceramsite, transportation, electricity and curing agent in dust disposal are the most significant contributors to most of environmental impacts categories results, accounting for 33.7%, 29.0% and 24.6% to the integrated impacts index, respectively. For non-sintering ceramsite, curing agent and electricity contribute 69.6% and 15.8% to the integrated impacts index, respectively. Based on these life cycle assessment results, recommendations for current plant operation and new plants planning are proposed.
- Published
- 2020
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