56 results on '"Baoliang Lv"'
Search Results
2. Oxygen vacancy enriched Cu-WO3 hierarchical structures for the thermal decomposition of ammonium perchlorate
- Author
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Jing Shi, Baoliang Lv, Haizhen Sun, Xiangying Xing, Huixiang Wang, and Lin Ge
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Inorganic Chemistry ,chemistry.chemical_compound ,Adsorption ,Materials science ,Chemical engineering ,chemistry ,Thermal decomposition ,Activation energy ,Lewis acids and bases ,Nanoflower ,Ammonium perchlorate ,Decomposition ,Catalysis - Abstract
The design and fabrication of efficient catalysts for ammonium perchlorate (AP) decomposition is crucial for the performance of composite solid propellants. Herein, a novel hierarchical structure material of Cu-WO3 nanowire arrays on a nanoflower flake (Cu-WO3 NANF) was synthesized by a facile hydrothermal reaction. The negatively charged (001) polar facets of hexagonal WO3 and the action of Cu2+ induced growth were two important factors for the formation of hierarchical structures. The Cu-WO3 NANF exhibited remarkable catalytic activity for the thermal decomposition of AP. The temperature and activation energy of high temperature AP decomposition were significantly decreased to 378.3 °C and 147.01 kJ mol−1, respectively, which are attributed to the more oxygen vacancies and lower band gap energy of the Cu-WO3 NANF. Thus, it was excited at a lower heat to produce activated species. Under the strong adsorption of Cu-WO3 NANF surface Lewis acid, the activated species can react with NH3 quickly and deeply to produce N2, N2O, NO2 and NO gases, accompanied by a heat release of up to 1118 J g−1. The proposed catalytic mechanism was further corroborated by the in situ TG-MS result. This facile strategy provided a new idea for the design of hierarchical catalysts, and our research opened up a new field for WO3 applications.
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- 2022
3. Furnace for in-situ characterization of the preoxidation of polyacrylonitrile (PAN) fibers by wide angle X-ray scattering (WAXS)
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Rongchao Chen, Li-Zhi Liu, Dongfeng Li, Zhihong Li, Baoliang Lv, Ying Shi, and Weifeng Huang
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In situ ,chemistry.chemical_compound ,Materials science ,Chemical engineering ,chemistry ,General Chemical Engineering ,Polyacrylonitrile ,Synchrotron radiation ,Wide-angle X-ray scattering ,Instrumentation ,General Environmental Science ,Characterization (materials science) - Abstract
Polyacrylonitrile (PAN) based carbon fibers possess high performance and wide applications. Preoxidation, as one of the crucial steps in the preparation of carbon fibers, refers to the process in w...
- Published
- 2021
4. Gas-Phase Catalytic Dehydration of Glycerol with Methanol to Methyl Glyceryl Ethers over Phosphotungstic Acid Supported on Alumina
- Author
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Ye Zhang, Laishuan Liu, Baoliang Lv, Guangxin Jia, and Yu Li
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General Chemical Engineering ,Glyceryl Ethers ,Ether ,General Chemistry ,Article ,Catalysis ,Cerium nitrate ,chemistry.chemical_compound ,Chemistry ,chemistry ,Nitric acid ,Glycerol ,Phosphotungstic acid ,Methanol ,QD1-999 ,Nuclear chemistry - Abstract
Glycerol can be dehydrated with methanol to produce methyl glyceryl ethers as biologicals and diesel fuel additives. Considering the high efficiency of mass transfer and product separation in the gas-solid catalytic process, a fixed-bed continuous-flow reactor was used to carry out the catalyst evaluation test of the process at 564 K. Compared with zirconium sulfate, lanthanum nitrate, and ammonium molybdate, phosphotungstic acid exhibits a higher target product selectivity. Through loading experiments, it was found that the optimal loading fraction of phosphotungstic acid on alumina is 10 wt %. After the alumina carrier is impregnated with nitric acid, the selectivity and yield of monomethyl glycerol ether can be effectively improved, and it has little effect on other products. A test of the addition amount of cerium nitrate as a promoter was carried out. It was shown in the test that when the addition amount of cerium nitrate is 10 wt %, the catalyst life increases from 2 to 3.5 h and the selectivity of dimethyl glycerol ether increases to 54.51%, which is twice the original. However, the selectivities of monomethyl glycerol ether and trimethyl glycerol ether decrease by one-half each. Through catalyst characterization, it was shown that carbon deposition on the catalyst surface is one of the reasons for catalyst deactivation.
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- 2021
5. Rapid synthesis of Cu2O hollow spheres at low temperature and their catalytic performance for the decomposition of ammonium perchlorate
- Author
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Jing Shi, Huixiang Wang, Huai-Zhong Xing, Tao-Tao Lv, Baoliang Lv, Hong-Mei Yang, and Jing-Pei Cao
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Ostwald ripening ,Materials science ,Reducing agent ,Thermal decomposition ,General Chemistry ,Condensed Matter Physics ,Ascorbic acid ,Ammonium perchlorate ,Catalysis ,symbols.namesake ,chemistry.chemical_compound ,Adsorption ,Chemical engineering ,chemistry ,Specific surface area ,symbols ,General Materials Science - Abstract
In catalytic reactions, a large specific surface area usually means more active sites. Hollow structures can provide lots of surface sites to catalyze the reaction or fix the reaction center, but the preparation process is mostly complex. In this work, using NH4+ as a structure-directing agent and ascorbic acid (AA) as a reducing agent, combined with the self-transformation process of metastable aggregated particles and the local Ostwald ripening mechanism, hollow Cu2O nanospheres with a large specific surface area (30.9 m2 g−1) were rapidly synthesized by a one-step method at low temperature. In the thermal decomposition of ammonium perchlorate (AP), it was found that the decomposition temperatures at low temperature and high temperature decreased by 31.6 °C and 125 °C, respectively. Compared with pure AP, the heat release increased by 1.5 times, and the reaction activation energy reduced by 56.0%. This is because the Cu2O hollow spheres have a larger specific surface area, and the adsorption capacity is improved owing to the loose and porous structure. The catalytic area and active sites for continuous reaction are increased, and thus the Cu2O hollow spheres exhibited excellent catalytic performance.
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- 2021
6. Ultrathin Nanosheet-Assembled, Phosphate Ion-Functionalized NiO Microspheres as Efficient Supercapacitor Materials
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Biao Qin, Hai Zhou, Ning Zhao, Baoliang Lv, and Min Kang
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Supercapacitor ,Materials science ,Hydrothermal reaction ,Non-blocking I/O ,Phosphate ion ,Energy Engineering and Power Technology ,Phosphate ,Microsphere ,chemistry.chemical_compound ,chemistry ,Chemical engineering ,Materials Chemistry ,Electrochemistry ,Chemical Engineering (miscellaneous) ,Hydrothermal synthesis ,Electrical and Electronic Engineering ,Nanosheet - Abstract
In this work, ultrathin nanosheet-assembled, phosphate ion-functionalized NiO (P-NiO) microspheres were prepared via a facile hydrothermal reaction and subsequent thermal annealing. The formation m...
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- 2020
7. CoP/RGO-Pd Hybrids with Heterointerfaces as Highly Active Catalysts for Ethanol Electrooxidation
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Yicong Xiao, Cheng-Meng Chen, Yue-Wen Mu, Gang-Ping Wu, Liancheng Wang, Baoliang Lv, Mengchao Wang, Huixiang Wang, and Ruimin Ding
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Ethanol ,Materials science ,Cobalt phosphide ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Direct-ethanol fuel cell ,01 natural sciences ,Combinatorial chemistry ,0104 chemical sciences ,Catalysis ,chemistry.chemical_compound ,chemistry ,General Materials Science ,0210 nano-technology ,Ethanol oxidation reaction ,Bond cleavage - Abstract
The ethanol oxidation reaction is of critical importance to the commercial viability of direct ethanol fuel cell technology. However, owing to the poor C-C bond cleavage capability, almost all ethanol oxidation is incomplete and suffers from low selectivity toward the C1 pathway. Herein, under the support of theoretical calculations that the heterointerfaces between CoP and Pd can reduce the energy barrier of C-C bond cleavage, rich heterointerfaces in CoP/RGO-Pd hybrids were designed to improve ethanol electrooxidation performance through enhancing the selectivity toward the C1 pathway. The experimental results show that the faradaic efficiency of the C1 pathway of CoP/RGO-Pd hybrids is as high as 27.6%, surpassing most reported catalysts in the literature. As a result of this enhancement, CoP/RGO-Pd10 exhibits mass activity as high as 4597 mA·mg
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- 2020
8. Edge-Activating CO2-Mediated Ethylbenzene Dehydrogenation by a Hierarchical Porous BN Catalyst
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Liancheng Wang, Rong Zhang, Baoliang Lv, Ruimin Ding, Xiaohua Chen, and Yuanying Wang
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Reaction mechanism ,010405 organic chemistry ,Chemistry ,General Chemistry ,Edge (geometry) ,010402 general chemistry ,01 natural sciences ,Ethylbenzene ,Catalysis ,0104 chemical sciences ,chemistry.chemical_compound ,Chemical engineering ,Dehydrogenation ,Selectivity ,Hierarchical porous - Abstract
The metal-free BN catalyst is a competitive candidate in oxidative dehydrogenation (ODH). The popular oxidant used is molecular O2, and the alternative soft oxidant, CO2 with better selectivity, is...
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- 2020
9. Enhanced Fischer-Tropsch synthesis performances of Fe/h-BN catalysts by Cu and Mn
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Qiang Chang, Hongwei Xiang, Jian Xu, Yong-Wang Li, Chenghua Zhang, Liancheng Wang, Xianzhou Wang, Baoliang Lv, and Yong Yang
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Materials science ,Iron oxide ,Fischer–Tropsch process ,02 engineering and technology ,General Chemistry ,Crystal structure ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Catalysis ,0104 chemical sciences ,chemistry.chemical_compound ,Physisorption ,chemistry ,X-ray photoelectron spectroscopy ,Chemical engineering ,0210 nano-technology ,Porosity ,Iron oxide nanoparticles - Abstract
A series of Fe/h-BN catalysts promoted with Cu or Mn were prepared for Fischer-Tropsch synthesis (FTS). The physicochemical properties, crystal structures and morphologies of the catalysts were characterized by N2 physisorption, FT-IR, TPR, XPS, XRD, MES and TEM. It is found that iron oxide nanoparticles are highly dispersed on h-BN matrix due to the anchoring effect of surface defects and the accommodation of porous structures of h-BN. The characterization results indicate that strong interaction between iron oxide and h-BN is present on un-promoted catalyst, which endows the h-BN supported iron catalyst with stable properties under FTS conditions but severely retards reduction of the catalyst. The addition of Cu to Fe/h-BN can to some extent overcome the strong interaction by introducing more sites for dissociating H2. It is observed that Cu promoter can increase the reduction or carburization degree and thus enhance the FTS activity. The addition of Mn to Fe/h-BN can weaken the strong interaction by altering the electron structure of iron species. And the electron-rich Fe species are responsible for easy reduction and the enhanced FTS performance. Besides, a higher activity can be realized by co-adding Cu and Mn to the Fe/h-BN catalyst. These results suggest that the synergistic effect of Mn and Cu can largely improve the performance of Fe/h-BN catalyst without impairing the stability of the catalyst. The present study paves a way to tailor the performances of FTS catalysts with h-BN as support.
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- 2020
10. Protection of highly active sites on Cu2O nanocages: an efficient crystalline catalyst for ammonium perchlorate decomposition
- Author
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Baoliang Lv, Liancheng Wang, Huixiang Wang, Xiaobo Ren, Jing-Pei Cao, Ruimin Ding, and Tao-Tao Lv
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Materials science ,Morphology (linguistics) ,Reducing agent ,Thermal decomposition ,General Chemistry ,Condensed Matter Physics ,Ammonium perchlorate ,Decomposition ,Catalysis ,chemistry.chemical_compound ,Nanocages ,chemistry ,Chemical engineering ,Etching (microfabrication) ,General Materials Science - Abstract
For crystalline catalysts with special morphology, the corners and edges are usually of high activities due to the presence of unsaturated coordination sites, so it will be an ideal strategy to promote catalytic properties by only keeping the corners and edges of such kinds of catalysts. In this work, a Cu2O tetradecahedral nanocage with plenty of corners and edges was formed by selectively etching the (111) and (100) facets on the basis of a simple top-down method, in which SDS was used as a protective agent to keep the active corners and edges while hydroxylamine hydrochloride was used as a reducing agent and an etchant. The decomposition of ammonium perchlorate (AP) was used as a probe reaction to test its catalytic performance. It was found that the low temperature decomposition (LTD) and high temperature decomposition (HTD) were reduced by 27.1 °C and 107 °C, respectively, and the heat release increased by three times in comparison with pure AP. The Cu2O nanocage exhibits excellent activity and high catalytic performance in the reaction. This work provides us an effective AP thermal decomposition catalyst and a simple strategy to fabricate a hollow structure with low-energy facets etched and highly active facets exposed.
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- 2020
11. Insight into the Effective Aerobic Oxidative Cross-Esterification of Alcohols over Au/Porous Boron Nitride Catalyst
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Zheng Tao, Rong Zhang, Huixiang Wang, Baoliang Lv, Liancheng Wang, Xiao Wang, and Xi Yang
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Reaction mechanism ,Materials science ,Radical ,02 engineering and technology ,Activation energy ,Methyl benzoate ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Photochemistry ,01 natural sciences ,0104 chemical sciences ,Catalysis ,chemistry.chemical_compound ,chemistry ,Boron nitride ,Benzyl alcohol ,Desorption ,General Materials Science ,0210 nano-technology - Abstract
Boron nitride (BN) has attracted great attention with an unexpected ability in aerobic catalysis. Still, its related probe reactions are relatively rare, and the effect of the BN-supported metal catalyst on O2 activation is still ambiguous, and opinions are varied. In this work, the porous BN (pBN)-supported Au catalyst with a porous structure and exposed edges exhibits high activity in the oxidative cross-esterification reactions between the aromatic and C1-C3 aliphatic alcohols at ambient temperature. The turnover frequency value for methyl benzoate is 118 h-1 at 30 °C, and the calculated apparent activation energy (Ea, 58 kJ/mol) is comparable to that of AuPd/TiO2, Ru/Al2O3, and PdBiTe catalysts. Combined with temperature-programmed desorption (TPD) results, the loading of Au enhances the desorption of O2 and the interaction with alcohols; thus, a synergistic effect between the O-rich pBN and Au is considered. The free-radical scavenger can dramatically suppress the conversion (∼6%), suggesting that the reaction proceeds via the O2* radicals. According to the vibration of νO-O, δOO-H, and νB-O-O-B detected by attenuated total reflectance-infrared spectroscopy (ATR-IR), we are prone to consider the oxygen activation route by the edge B atoms. Then, a possible L-H reaction mechanism was proposed: benzyl alcohol and O2 adsorb on the Au/pBN initially, then O2 is converted to O2*, and the α-H elimination proceeds; as the semi-acetal formed, another α-H elimination proceeds and methyl benzoate is finally formed.
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- 2019
12. The role of surface N H groups on the selective hydrogenation of cinnamaldehyde over Co/BN catalysts
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Xiaobo Ren, Zheng Tao, Liancheng Wang, Baoliang Lv, Xi Yang, and Rong Zhang
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chemistry.chemical_classification ,Hydrogen bond ,General Physics and Astronomy ,chemistry.chemical_element ,02 engineering and technology ,Surfaces and Interfaces ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,Aldehyde ,Medicinal chemistry ,Cinnamaldehyde ,0104 chemical sciences ,Surfaces, Coatings and Films ,Catalysis ,chemistry.chemical_compound ,Adsorption ,chemistry ,Boron nitride ,0210 nano-technology ,Selectivity ,Cobalt - Abstract
The surface chemistry of catalyst plays a vital role in the catalytic process. And the effects of surface groups of porous boron nitride (p-BN) on the hydrogenation reaction have not been studied in detailed. In this work, two main surface species of Co/p-BN catalyst were tuned thermally and their roles on the hydrogenation reaction were discriminated by α, β-unsaturated aldehyde hydrogenation reaction. The surface B O content decreased at higher reduction temperature and the cobalt phase changed from CoO to the mixture of CoO and Co0. The Co/p-BN-500 exhibited the highest selectivity to C O hydrogenation. And its turnover frequency (TOF) of 13.2 h−1 is close to the optimal value of reported cobalt catalysts. When the reaction proceeds, hydrogenation rate of C O increases but that of C C decreases gradually, thus a surface groups variation was expected at the initial period. Further in-situ FTIR spectra showed the band intensity of edge N H increases as the adsorption proceeds at 50°С but it decreases as the temperature rise to 200°С, in combined with the shift of C O adsorption peak, a intermolecular hydrogen bond between edge N H and the terminal C O group was suggested, which account for the better selectivity to C O than C C.
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- 2019
13. Micron iron oxide particles with thickness-controllable carbon coating for Ni-Fe battery
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Ruimin Ding, Yufeng Yang, Qunjie Li, Mengchao Wang, Liancheng Wang, Baoliang Lv, Xianfen Wang, Liyi Shi, Huixiang Wang, and Xiaobo Ren
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Battery (electricity) ,Materials science ,Passivation ,General Chemical Engineering ,Iron oxide ,chemistry.chemical_element ,02 engineering and technology ,Conductivity ,engineering.material ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Anode ,chemistry.chemical_compound ,chemistry ,Coating ,Electrode ,Electrochemistry ,engineering ,Composite material ,0210 nano-technology ,Carbon - Abstract
Coating actives with carbon is an effective way to improve the performance of Ni Fe battery, and relevant study has focused on the nanoFe/FeOx, while the micron particles used in the industry have been usually ignored. Herein, we achieve the uniform and thickness-controllable carbon coating for the micron-sized dodecahedral Fe3O4, and study the influence of the carbon thickness on the performance of the Fe anode in details. As a result, capacity, rate performance and stability are improved with the increase of carbon coating because of lower charge-transfer resistance and more complete structure. However, for the first plateau (Fe0→Fe2+) which is typically applied in the industry, the improvement of the carbon coating is limited with the thickness of the carbon, owing to insufficient impact of mitigating passivation. For the second and third plateaus (Fe2+→Fe3+), with the increase of the carbon coating, the capacity and rate performance are both markedly improved because a more completed structure can better promise the conductivity. As the thickness of the carbon coating is 20 nm, the electrode exhibits 141 mAh g−1 at a high current density of 36 A g−1. These results are of great significance to the development of industrial Ni-Fe battery.
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- 2019
14. Fe containing MoO3 nanowires grown along the [110] direction and their fast selective adsorption of quasi-phenothiazine dyes
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Zhong Liu, Jianbo Wu, Liancheng Wang, Fan Li, Huixiang Wang, Ying Cao, Ruimin Ding, Baoliang Lv, Jing Wang, and Xiaobo Ren
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Hydrogen bond ,Inorganic chemistry ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,0104 chemical sciences ,chemistry.chemical_compound ,Isoelectric point ,Adsorption ,chemistry ,Phenothiazine ,Specific surface area ,Selective adsorption ,General Materials Science ,Toluidine ,0210 nano-technology ,Methylene blue - Abstract
Herein, MoO3 nanowires (Fe–MoO3 NWs) along the [110] direction were successfully synthesized in the presence of Fe3+ cations. The Fe–MoO3 NWs present a large specific surface area of 174.7 m2 g−1 and rich surface –OH groups, and the possible formation mechanism of such a structure is due to the adsorption of Fe3+ cations toward non-(110) planes of MoO3 in solution with pH greater than its isoelectric point. The obtained Fe–MoO3 NWs show excellent and highly selective adsorption capacity toward quasi-phenothiazine dyes (methylene blue, toluidine blue, azure I, and acridine orange). The dye removal rate could reach 99% in 3 min, and the maximum adsorption capacity is up to 144.3 mg g−1 and the adsorption is up to 28.86 mg g−1 per minute, which is 11 times greater than that of pure MoO3 and far greater than that of the recently reported MoO3 nanostructures. This excellent selective adsorption performance of Fe–MoO3 NWs was mainly attributed to the enhanced chemical adsorption of quasi-phenothiazine dyes by rich surface –OH groups and Fe species through hydrogen bond and coordination bond adsorption with N and S, respectively, which was confirmed by adsorption isotherms and adsorption kinetics. These results suggest the potential application of Fe–MoO3 NWs in the field of water pollution treatment.
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- 2019
15. Rapid microwave-assisted hydrothermal synthesis of CeO2 octahedra with mixed valence states and their catalytic activity for thermal decomposition of ammonium perchlorate
- Author
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Jing Shi, Yequn Liu, Baoliang Lv, Haizhen Sun, Huixiang Wang, and Xiaobo Ren
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Materials science ,Thermal decomposition ,chemistry.chemical_element ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Ammonium perchlorate ,01 natural sciences ,0104 chemical sciences ,Catalysis ,Inorganic Chemistry ,Thermogravimetry ,Crystallography ,Cerium ,chemistry.chemical_compound ,Differential scanning calorimetry ,chemistry ,Octahedron ,Hydrothermal synthesis ,0210 nano-technology - Abstract
Cerium dioxide (CeO2) octahedra were synthesized by a facile microwave-assisted hydrothermal method. The structure and morphology were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results showed that octahedra were enclosed by eight (111) facets with an edge length of 180 nm. The possible growth mechanism of CeO2 octahedra was proposed by adjusting the reaction temperature, solvent, molar ratios of polyvinyl pyrrolidone (PVP)/Ce3+ and reaction time. The formation of the octahedra was attributed to the oxygen terminated structure of (111) facets and the steric hindrance effect of PVP. Furthermore, the catalytic activity of CeO2 octahedra on the thermal decomposition of ammonium perchlorate (AP) was investigated by thermogravimetry and differential scanning calorimetry (TG-DSC). Compared with cubes, the CeO2 octahedra exhibited enhanced activity on the decomposition of AP. Upon addition of 4 wt% CeO2 octahedra, the ending mass loss temperature of AP decreased by 52.1 °C. The higher catalytic activity was attributed to the synergistic effect between the exposed (111) facets and high concentration of oxygen vacancies that arised from the mixed valence state of Ce ions.
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- 2019
16. Enhanced role of graphitic-N on nitrogen-doped porous carbon ball for direct dehydrogenation of ethylbenzene
- Author
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Xi Yang, Conghui Wang, Liancheng Wang, Baoliang Lv, and Li Qin
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biology ,010405 organic chemistry ,Process Chemistry and Technology ,Doping ,technology, industry, and agriculture ,Active site ,chemistry.chemical_element ,010402 general chemistry ,Photochemistry ,01 natural sciences ,Nitrogen ,Ethylbenzene ,Catalysis ,0104 chemical sciences ,Styrene ,chemistry.chemical_compound ,Delocalized electron ,chemistry ,biology.protein ,Dehydrogenation ,Physical and Theoretical Chemistry - Abstract
Nitrogen doping is an efficient strategy to improve the catalytic activity of carbocatalysts in direct dehydrogenation reactions. The interpretation of enhanced activity is now mainly attributed to the strengthened basicity. On the other side of doping, electronic properties that differed in various nitrogen doping configurations, however, were barely considered. Herein, to elucidate the role of graphitic N, pyridinic N and pyrrolic N, N-doped porous carbon balls with tunable contents of these nitrogen species were used as moulded carbocatalysts for steam-free direct dehydrogenation of ethylbenzene to styrene. Along with C O groups that were commonly certified as active sites on carbocatalysts, graphitic N contributes to the styrene yield. The former serves as active site that directly activates and dissociates C–H bond, while the latter one provides additional electrons into the delocalized π-system and leads to improved chemical reactivity of C O. The loss of C O active sites is not only attributed to the carbon deposition as illustrated by the elevated area ratio of D3 to G band in Raman spectra, but also its failed regeneration from intermediate hydroxyl groups (C–OH), which was proved by the tiny thermal decomposed products of CO and H2O as detected by the on-line mass spectrometry and gas chromatography.
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- 2019
17. Bubble-template synthesis of WO3·0.5H2O hollow spheres as a high-activity catalyst for catalytic oxidation of benzyl alcohol to benzaldehyde
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Zhi Liu, Huixiang Wang, Baoliang Lv, Dong Jiang, and Xiaobo Ren
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Materials science ,Nanoparticle ,Foaming agent ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,0104 chemical sciences ,Catalysis ,law.invention ,Solvent ,Benzaldehyde ,chemistry.chemical_compound ,Catalytic oxidation ,chemistry ,Chemical engineering ,law ,Benzyl alcohol ,General Materials Science ,Calcination ,0210 nano-technology - Abstract
Although significant progress has been made in WO3 hollow spheres, it is still a challenge to synthesize WO3·0.5H2O hollow spheres. Herein, a strategy for the preparation of well-shaped WO3·0.5H2O hollow spheres was developed by a facile bubble-template method using urea as a foaming agent in the solvothermal process with EtOH–H2O mixture solvent. In this process, the growth of WO3·0.5H2O nanoparticles is limited by N-containing organic compounds, thus these nanoparticles tend to agglomerate along the surface of bubbles (CO2 and NH3) to fabricate hollow spheres with pores formed in the wall, and after low temperature calcination, pure WO3·0.5H2O hollow spheres are obtained. The obtained WO3·0.5H2O hollow spheres exhibit enhanced activity in catalytic oxidation of benzyl alcohol to benzaldehyde: the conversions of benzyl alcohol, 4-methyl, 3-methyl, 2-methyl, 4-bromo and 4-nitro benzyl alcohol are 99.2%, 95.0%, 97.1%, 86.7%, 98.0%, 90.6%, respectively, and the selectivities to corresponding benzaldehydes are all greater than 98%. The high activity of WO3·0.5H2O hollow spheres could be attributed to surface –OH groups and the hollow and porous structure.
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- 2019
18. CoP porous hexagonal nanoplates in situ grown on RGO as active and durable electrocatalyst for hydrogen evolution
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Gang-Ping Wu, Mengchao Wang, Ruimin Ding, Li Qin, Liancheng Wang, Jing Wang, Baoliang Lv, and Xinmin Cui
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Tafel equation ,Materials science ,Graphene ,General Chemical Engineering ,Oxide ,02 engineering and technology ,Overpotential ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Electrocatalyst ,01 natural sciences ,Energy storage ,0104 chemical sciences ,law.invention ,Catalysis ,chemistry.chemical_compound ,Chemical engineering ,chemistry ,law ,Electrochemistry ,0210 nano-technology ,Porosity - Abstract
The development of efficient and low-cost hydrogen evolution reaction (HER) catalysts is critical for energy storage and conversion devices. Herein, we develop a facile method to fabricate a novel hybrid by in situ growing CoP porous nanoplates on reduced graphene oxide (RGO). The hybrid shows excellent HER performance in acid media with a low Tafel slope of 57 mV dec−1, small onset overpotential of 76 mV and long-term durability with 86.3% current density retention after 10 h electrocatalysis. The superb HER activity can be ascribed to the unique structure of porous hexagonal nanoplates. On the one hand, the porous structure provides abundant active sites for HER. On the other hand, hexagonal nanoplates provide large contact with RGO, enhancing the charge transfer ability. In addition, the hybrid with such structure shows good stability under ambient atmosphere and can maintain the initial HER activity even after six months of storage. This work demonstrates that large contact between active component and conductive support is not only beneficial to the HER activity and durability, but also beneficial to the stability of material itself.
- Published
- 2018
19. Facets Matching of Platinum and Ferric Oxide in Highly Efficient Catalyst Design for Low-Temperature CO Oxidation
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Tao Deng, Chengyi Song, Jianbo Wu, Wenlong Chen, Rong Huang, Baoliang Lv, Fan Li, Xiaobo Ren, Wen Shang, Chao Li, Hong Zhu, Peng Tao, and Yanling Ma
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Materials science ,010405 organic chemistry ,Oxide ,Order (ring theory) ,chemistry.chemical_element ,engineering.material ,010402 general chemistry ,Heterogeneous catalysis ,01 natural sciences ,0104 chemical sciences ,Catalysis ,chemistry.chemical_compound ,Adsorption ,chemistry ,medicine ,engineering ,Physical chemistry ,Ferric ,General Materials Science ,Noble metal ,Platinum ,medicine.drug - Abstract
Rational design of supported noble metal is of great importance for highly efficient heterogeneous catalysts. On the basis of the distinct adsorption characteristics of noble metal and transition-metal oxides toward O2 and CO, the overall catalytic performance of CO oxidation reaction could be further modified by controlling the surface property of the materials to achieve optimal adsorption activity. Here, we studied the influence of facets matching between both platinum and ferric oxide support on CO conversion efficiency. It shows that the activities of four catalysts rank following the order of Pt{100}/α-Fe2O3{104} > Pt{100}/α-Fe2O3{001} > Pt{111}/α-Fe2O3{001} > Pt{111}/α-Fe2O3{104}. The strong metal–support interaction and adsorption energy varying with matched enclosed surface are demonstrated by density functional theory based on the projected d-band density of states. Compared with the other three cases, the combination of Pt{100} and α-Fe2O3{104} successfully weakens CO poisoning and provides pro...
- Published
- 2018
20. Synergistic enhancement of oxygen reduction reaction with BC3 and graphitic-N in boron- and nitrogen-codoped porous graphene
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Liancheng Wang, Baoliang Lv, Ruimin Ding, Xiaohua Chen, Li Qin, Xi Yang, and Zhanfeng Zheng
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Battery (electricity) ,Chemistry ,Graphene ,chemistry.chemical_element ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Nitrogen ,Catalysis ,0104 chemical sciences ,law.invention ,Chemical engineering ,law ,Density functional theory ,Physical and Theoretical Chemistry ,0210 nano-technology ,Boron ,Porosity ,Power density - Abstract
Rational design and optimization of metal-free electrocatalysts for the oxygen reduction reaction (ORR) is crucial for fuel cells and metal-air batteries. However, identifying design principle that links the active sites and their synergistic effects is far from satisfactory, especially for B,N-codoped graphene. Herein, we provide four B,N-codoped porous graphenes with tunable contents of pyridinic N, graphitic N, BC3 and C-B(N)O. BC3 shows multiple-fold specific activity compared with graphitic N and pyridinic N, while C-B(N)O offers no positive contribution. Density functional theory calculations indicate that the synergistic effect between graphitic N and BC3 can effectively facilitate the reduction of O2. These pinpoint that graphitic N and BC3 are the main active sites among various nitrogen or/and boron doping configurations. The most active catalyst exhibits superior activity than the commercial Pt/C catalyst using the RDE method in alkaline media, and displays comparable power density to Pt/C catalyst in Zn-air battery.
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- 2018
21. Design and facile one-step synthesis of FeWO4/Fe2O3 di-modified WO3 with super high photocatalytic activity toward degradation of quasi-phenothiazine dyes
- Author
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Zhanfeng Zheng, Conghui Wang, Ruimin Ding, Zhong Liu, Li Qin, Liancheng Wang, Huixiang Wang, Baoliang Lv, and Xinmin Cui
- Subjects
Materials science ,Valence (chemistry) ,Process Chemistry and Technology ,Radical ,Nanoparticle ,Nanotechnology ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Photochemistry ,01 natural sciences ,Catalysis ,0104 chemical sciences ,chemistry.chemical_compound ,Adsorption ,chemistry ,Phenothiazine ,Photocatalysis ,Toluidine ,0210 nano-technology ,Methylene blue ,General Environmental Science - Abstract
For most of WO 3 , a visible-light-driven photocatalyst, its barrier in photocatalytic degradation is the low conduction band (CB) potential that can not reduce O 2 to O 2 − and HO 2 radicals and thus results in fast recombination of electron/hole. With this in mind, a new active FeWO 4 /Fe 2 O 3 di-modified WO 3 was designed and prepared via by a straightforward but effective strategy by introducing of FeWO 4 and Fe 2 O 3 clusters (or nanoparticles) on WO 3 . The performance of di-modified WO 3 showed super high photocatalytic activity in degrading quasi-phenothiazine dyes of Methylene blue (MB), Toluidine blue (TB), Azure I (AI) and Acridine orange (AO) under visible light irradiation, and the corresponding k values are 5.3, 4.4, 3.8 and 5.8 times larger than that of pure WO 3 , respectively. This improvement was mainly due to the fact that photoexcited electrons can migrate to the matching CB of firmly and highly dispersed FeWO 4 and Fe 2 O 3 , then be consumed rapidly by a valence decrease from Fe 3+ to Fe 2+ and Fenton reaction between Fe 2+ and H 2 O 2 . And the strong adsorption of Fe species toward N and S (or N) elements in quasi-phenothiazine dyes, also positively promoted the efficiency of degradation.
- Published
- 2018
22. Scalable synthesis of quasi-monodispersed BN colloidal nanocrystals by 'solvent cutting' and their anti-electrochemical corrosion coating
- Author
-
Li Qin, Liyi Shi, Liancheng Wang, Baoliang Lv, Xi Yang, and Ruimin Ding
- Subjects
Materials science ,General Chemical Engineering ,chemistry.chemical_element ,Nanotechnology ,02 engineering and technology ,General Chemistry ,engineering.material ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Industrial and Manufacturing Engineering ,0104 chemical sciences ,Amorphous solid ,Colloid ,Crystallinity ,chemistry ,Nanocrystal ,Coating ,Impurity ,engineering ,Environmental Chemistry ,Grain boundary ,0210 nano-technology ,Boron - Abstract
Hexagonal boron nitride nanosheets (BNNSs), which show outstanding thermal conductivity and chemical stability, have drawn more and more attention in recent years. However, the limited yield, dispersivity and the polydispersed size of the exfoliated ones hinder their further application. Here, we present a method of effective and scalable synthesis of quasi-monodispersed BN colloidal nanocrystals by “solid-state synthesis” combined with “solvent cutting” technique. The key of the technique is the imperfect nitridation of the BO species, which yield the boron oxides and amorphous BN that coexist with the well crystallized BN domains. As the impurities that separate the well crystallized BN domains are removed, the BN skeleton with better crystallinity is remained. The BN colloidal nanocrystals are obtained when the solvents cut the weak grain boundary in BN skeleton. The lateral size of as-prepared BN colloidal nanocrystals could be well controlled for 3 nm, 10 nm and 20 nm. The zeta potentials of colloid are below −30 mV in a pH range of 5–12. That means the BN colloid can keep high colloidal stability over a wide pH range. As an exemplary application of colloidal BN nanocrystals, the BN film is coated on the copper foil by a simple dip-coating method. The coated copper foil shows remarkable anti-electrochemical corrosion property. This study not only paves a way for the synthesis of colloidal BN nanocrystals, but also gives an alternative choice for a facile and low cost protective BN coating.
- Published
- 2018
23. Thermal induced BCN nanosheets evolution and its usage as metal-free catalyst in ethylbenzene dehydrogenation
- Author
-
Zhenwei Zhang, Liancheng Wang, Conghui Wang, Jianghong Wu, Ruimin Ding, and Baoliang Lv
- Subjects
Materials science ,Thermal desorption spectroscopy ,General Physics and Astronomy ,chemistry.chemical_element ,Nanotechnology ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,Ethylbenzene ,Catalysis ,chemistry.chemical_compound ,Specific surface area ,Desorption ,Dehydrogenation ,biology ,Active site ,Surfaces and Interfaces ,General Chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,0104 chemical sciences ,Surfaces, Coatings and Films ,chemistry ,Chemical engineering ,biology.protein ,0210 nano-technology ,Carbon - Abstract
Compared with mushroomed progress in metal-free C-rich BCN catalysts, little is known about the BN-rich BCN or even BN ones. Its related study has drawn great interest recently but still in its infancy stage. In this study, three kinds of BCN nanosheets (NSs) with tuned surface carbon contents (5.5–14.3%), specific surface area (SSA, 82–290 m2/g) and morphologies (ultrathin nanosheets, triangular plates) were fabricated through a solid state reaction by simply adjusting the reaction temperature, and those effects on the ethylbenzene dehydrogenation performances were studied in CO2 atmosphere. The morphology evolution of BCN NSs from ultrathin nanosheets to the triangular plates was observed and control experiments were carried out. The BCN nanosheets show relatively strong interaction with CO2 and distinct CO2 absorption properties. The CO2 temperature programmed desorption also indicates that the desorption peaks of CO2 are above 400 °C, enabling them potential CO2 utilization catalysts. A weak association was found between the surface C contents and the catalytic performance as it normalized with SSA, and the B-O species could be taken as an active site in CO2 atmosphere. Though much progress still needed, it is convincing that the BCN catalyst could be a promising metal-free catalyst in dehydrogenation beyond carbocatalyst.
- Published
- 2017
24. Facile synthesis of self-assembled ultrathin α-FeOOH nanorod/graphene oxide composites for supercapacitors
- Author
-
Baoliang Lv, Xiaoping Wang, Yong Yang, Chengmeng Chen, Yuxue Wei, Ruimin Ding, Chenghua Zhang, Yi Wang, Jian Xu, and Yong-Wang Li
- Subjects
Supercapacitor ,Materials science ,Graphene ,Composite number ,Oxide ,02 engineering and technology ,Electrolyte ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,law.invention ,Biomaterials ,chemistry.chemical_compound ,Colloid and Surface Chemistry ,X-ray photoelectron spectroscopy ,chemistry ,law ,Nanorod ,Crystallite ,Composite material ,0210 nano-technology - Abstract
A one-pot facile, impurity-free hydrothermal method to synthesize ultrathin α-FeOOH nanorods/graphene oxide (GO) composites is reported. It is directly synthesized from GO and iron acetate in water solution without inorganic or organic additives. XRD, Raman, FT-IR, XPS and TEM are used to characterize the samples. The nanorods in composites are single crystallite with an average diameter of 6 nm and an average length of 75 nm, which are significantly smaller than GO-free α-FeOOH nanorods. This can be attributed to the confinement effect and special electronic influence of GO. The influences of experimental conditions including reaction time and reactant concentration on the sizes of nanorods have been investigated. It reveals that the initial Fe2+ concentration and reaction time play an important role in the synthetic process. Furthermore, a possible nucleation-growth mechanism is proposed. As electrode materials for supercapacitors, the α-FeOOH nanorods/GO composite with 20% iron loading has the largest specific capacitance (127 F g−1 at 10 A g−1), excellent rate capability (100 F g−1 at 20 A g−1) and good cyclic performance (85% capacitance retention after 2000 cycles), which is much better than GO-free α-FeOOH nanorods. This unique structure results in rapid electrolyte ions diffusion, fast electron transport and high charging-discharging rate. In virtue of the superior electrochemical performance, the α-FeOOH nanorods/GO composite material has a promising application in high-performance supercapacitors.
- Published
- 2017
25. The adsorption behavior and mechanism of Cr(VI) on 3D hierarchical α-Fe 2 O 3 structures exposed by (0 0 1) and non-(0 0 1) planes
- Author
-
Wu Li, Baoliang Lv, Zhong Liu, Yaping Dong, and Ruitao Yu
- Subjects
Aqueous solution ,General Chemical Engineering ,Inorganic chemistry ,Nanoparticle ,Langmuir adsorption model ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Industrial and Manufacturing Engineering ,Hydrothermal circulation ,0104 chemical sciences ,symbols.namesake ,chemistry.chemical_compound ,Adsorption ,chemistry ,Chemisorption ,symbols ,Glycerol ,Environmental Chemistry ,Nanorod ,0210 nano-technology - Abstract
Two kinds of 3D hierarchical α-Fe 2 O 3 nanoparticles, flower-like structure with the (0 0 1) plane predominantly exposed on petals and urchin-like structure with nanorods grown along [0 0 1] direction, have been synthesized under the influence of glycerol by a facile hydrothermal method. It is proposed that the Fe(III)–glycerol micro-reaction units that selectively adsorb to (0 0 1) or other planes result in different morphologies. The adsorption of Cr(VI) from aqueous solution onto these α-Fe 2 O 3 nanoparticles showed that the removal efficiency up to 98.5% and 88.8% in 25 mg/L Cr(VI) solution, and the adsorption capacity reaches to 34.4 mg/g and 26.0 mg/g without pH adjustment. The adsorption kinetic is well described by the pseudo-second-order model and the Cr(VI) adsorption on the adsorbent agrees well with the Langmuir model. Lower surface areas and more excellent adsorption property associates with the chemisorption of Cr(VI) onto α-Fe 2 O 3 (0 0 1), which is achieved by coordination between Cr(VI) and doubly or triply coordinated hydroxyl groups on α-Fe 2 O 3 surface.
- Published
- 2017
26. Iron cation-induced biphase symbiosis of h-WO3/o-WO3·0.33H2O and their crystal phase transition
- Author
-
Conghui Wang, Xiaobo Ren, Liancheng Wang, Baoliang Lv, Ruimin Ding, and Huixiang Wang
- Subjects
Phase transition ,Morphology (linguistics) ,Hexagonal crystal system ,Chemistry ,Inorganic chemistry ,Nanoparticle ,Tungsten oxide ,02 engineering and technology ,General Chemistry ,Software simulation ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,Hydrothermal circulation ,0104 chemical sciences ,Crystal ,Crystallography ,General Materials Science ,0210 nano-technology - Abstract
Herein, tungsten oxide hexagonal prisms with a biphase of h-WO3 and o-WO3·0.33H2O were prepared by a facile hydrothermal method using Fe3+ cations. The combination of instrumental characterization and software simulation proved that two phases coexisted in one nanoparticle with same morphology. The ratio of two phases could be changed by adjusting the concentration of Fe3+ cations. On the basis of controlled experiments, a mechanism was proposed to illustrate the formation of this biphase WO3 structure, and it was also proved that the self-growth of Fe species was unfavorable for the coexistence of two phases.
- Published
- 2017
27. The role of CO2 in dehydrogenation of ethylbenzene over pure α-Fe2O3 catalysts with different facets
- Author
-
Jing Shi, Jing Zhang, Chenghua Zhang, Baoliang Lv, Xinmin Cui, Conghui Wang, and Liancheng Wang
- Subjects
Reaction conditions ,Superheated steam ,Nanotechnology ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Ethylbenzene ,Catalysis ,0104 chemical sciences ,Styrene ,chemistry.chemical_compound ,chemistry ,Nanocrystal ,Chemical engineering ,Dehydrogenation ,Physical and Theoretical Chemistry ,0210 nano-technology ,Science, technology and society - Abstract
The replacement of superheated steam with CO 2 for ethylbenzene (EB) dehydrogenation to produce styrene (ST) is of great importance from both scientific and practical perspectives, while it is still a big challenge to design and synthesize catalysts for dehydrogenation in the presence of CO 2 . Research into shape-controlled nanocrystals has proved that well-defined facets are of great importance for understanding the catalytic phenomena due to their definite surface structure. In the present work, α-Fe 2 O 3 nanocrystals enclosed by various crystal facets provide us the clue to understand the role of CO 2 in dehydrogenation. O(III) (the triply coordinated surface oxygen atom) is found to play an important role in activating CO 2 under reaction conditions, which is supported by both experimental and theoretical results. These results have deepened knowledge about the role of CO 2 in dehydrogenation over pure α-Fe 2 O 3 catalysts, which is significant in designing relative catalysts rationally.
- Published
- 2017
28. Facile synthesis of porous nitrogen-doped holey graphene as an efficient metal-free catalyst for the oxygen reduction reaction
- Author
-
Conghui Wang, Liancheng Wang, Jianghong Wu, Ruimin Ding, Chenghua Zhang, Yao Xu, Li Qin, Huixiang Wang, and Baoliang Lv
- Subjects
Materials science ,Inorganic chemistry ,Nanoparticle ,chemistry.chemical_element ,02 engineering and technology ,engineering.material ,010402 general chemistry ,01 natural sciences ,law.invention ,Catalysis ,law ,General Materials Science ,Electrical and Electronic Engineering ,Porosity ,Graphene ,Graphene foam ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Nitrogen ,Atomic and Molecular Physics, and Optics ,0104 chemical sciences ,chemistry ,engineering ,Noble metal ,0210 nano-technology ,Pyrolysis - Abstract
Nitrogen-doped graphene is a promising candidate for the replacement of noble metal-based electrocatalysts for oxygen reduction reactions (ORRs). The addition of pores and holes into nitrogen-doped graphene enhances the ORR activity by introducing abundant exposed edges, accelerating mass transfer, and impeding aggregation of the graphene sheets. Herein, we present a straightforward but effective strategy for generating porous holey nitrogen-doped graphene (PHNG) via the pyrolysis of urea and magnesium acetate tetrahydrate. Due to the combined effects of the in situ generated gases and MgO nanoparticles, the synthesized PHNGs featured not only numerous out-of-plane pores among the crumpled graphene sheets, but also interpenetrated nanoscale (5–15 nm) holes in the assembled graphene. Moreover, the nitrogen doping configurations of PHNG were optimized by post-thermal treatments at different temperatures. It was found that the overall content of pyridinic and quaternary nitrogen positively correlates with the ORR activity; in particular, pyridinic nitrogen generates the most desirable characteristics for the ORR. This work reveals new routes for the synthesis of PHNG-based materials and elucidates the contributions of various nitrogen species to ORRs.
- Published
- 2016
29. Systematic shape evolution of Co3O4nanocrystals from octahedra to spheres under the influence of C2O42−and PVP
- Author
-
Min Kang, Hai Zhou, Dong Wu, and Baoliang Lv
- Subjects
Materials science ,Oxide ,Nanotechnology ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,0104 chemical sciences ,Nanomaterials ,Metal ,Crystal ,chemistry.chemical_compound ,Adsorption ,Octahedron ,Nanocrystal ,Chemical engineering ,chemistry ,visual_art ,visual_art.visual_art_medium ,General Materials Science ,Facet ,0210 nano-technology - Abstract
A series of Co3O4 nanocrystals with systematic shape evolution from octahedra to corner-truncated octahedra, corner-truncated cubes, globate polyhedra and micro-spheres were successfully synthesized under the influence of C2O42− and PVP. It was proved that crystal facet growth limitation caused by the adsorption of C2O42− and PVP on the surface of Co3O4 particles played a crucial role in this shape evolution process. Besides obtaining a series of intermediate Co3O4 nanocrystals exposing different facets, this strategy could also show the relationship between these structures. The present work extends the PVP-assisted method to realize the shape evolution process of metal oxide nanomaterials.
- Published
- 2016
30. Synthesis and catalytic property of facet-controlled Co3O4structures enclosed by (111) and (113) facets
- Author
-
Hai Zhou, Min Kang, Baoliang Lv, and Dong Wu
- Subjects
High energy ,Thermal decomposition ,Nanotechnology ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Condensation reaction ,Ammonium perchlorate ,01 natural sciences ,0104 chemical sciences ,Catalysis ,chemistry.chemical_compound ,Adsorption ,chemistry ,Chemical engineering ,General Materials Science ,Chelation ,Facet ,0210 nano-technology - Abstract
Co3O4 microparticles, with many smooth quadrihedrons on the surface, were hydrothermally synthesized under the influence of EDTA2− anions. Due to the excellent chelating and capping ability of EDTA2−, the as-obtained Co3O4 microparticles were mainly enclosed by (111) and (113) facets or their equivalent facets. On the basis of condition-dependent experiments, a dehydration condensation reaction assisted by the limitation effects of EDTA2− adsorbed on the surfaces of Co3O4 was proposed to explain the growth process of the cubic crystalline Co3O4 microparticles. The as-obtained Co3O4 microparticles could catalyze the thermal decomposition of ammonium perchlorate (AP) effectively due to the exposure of the high energy facets.
- Published
- 2016
31. Ultrathin N-rich boron nitride nanosheets supported iron catalyst for Fischer–Tropsch synthesis
- Author
-
Conghui Wang, Baoliang Lv, Yao Xu, Jianghong Wu, Jiangang Chen, Li Qin, and Liancheng Wang
- Subjects
Materials science ,General Chemical Engineering ,Inorganic chemistry ,Nanoparticle ,Fischer–Tropsch process ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Heterogeneous catalysis ,01 natural sciences ,0104 chemical sciences ,Catalysis ,chemistry.chemical_compound ,Chemical engineering ,chemistry ,Boron nitride ,0210 nano-technology ,Dispersion (chemistry) ,Porosity ,Selectivity - Abstract
The boron nitride nanosheets (BNNSs) have attracted great interest in the field of energy storage and heterogeneous catalysis. In this paper, BNNSs supported iron (Fe/BNNSs) catalysts were prepared by one-pot solid state reaction and used in Fischer–Tropsch synthesis (FTS) for the first time. The microscopic structure, morphology and metal–support interaction of the Fe/BNNSs catalysts were investigated by TEM, FT-IR, 1H MAS NMR and H2-TPR. The average thickness of the N-rich BNNSs support was 4–8 nm, and the mean size of the iron nanoparticles was 25–40 nm. The CO conversion, CH4 and C5+ selectivity of typical Fe/BNNSs catalyst with 33 wt% Fe-loading were 47%, 13.7% and 48% at 270 °C, respectively. No obvious deactivation was observed even after 270 h running. The conversion, selectivity and the iron time yield (FTY) of Fe/BNNSs catalysts were highly related to the loading, dispersion of iron nanoparticles. The lower loading and better dispersion of the iron nanoparticles in Fe/BNNSs catalyst resulted in the better FTY and C5+ selectivity. The N-rich defects of BNNSs and porous structure of BNNSs anchored active phases to prevent them from growing larger. Therefore, the BNNSs support plays an important role in retarding the catalyst from deactivation.
- Published
- 2016
32. Nonspherical hollow α-Fe2O3 structures synthesized by stepwise effect of fluoride and phosphate anions
- Author
-
Conghui Wang, Jing Shi, Baoliang Lv, Xinmin Cui, Chenghua Zhang, Huixiang Wang, Yao Xu, Liancheng Wang, and Jianghong Wu
- Subjects
Materials science ,Nanostructure ,Renewable Energy, Sustainability and the Environment ,Nanoparticle ,Nanotechnology ,02 engineering and technology ,General Chemistry ,Hematite ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Phosphate ,01 natural sciences ,0104 chemical sciences ,chemistry.chemical_compound ,Dodecahedron ,chemistry ,Chemical engineering ,visual_art ,visual_art.visual_art_medium ,Photocatalysis ,Hydrothermal synthesis ,General Materials Science ,0210 nano-technology ,Fluoride - Abstract
Despite the significant progress in making hollow structures, it is still a challenge to synthesize some specialized hollow structures. In the present work, we obtained a new hollow hematite structure, tube-in-dodecahedron, by using the stepwise influences of fluoride and phosphate anions. Based on condition-dependent experiments, we proposed a “nucleation–aggregation–recrystallition and etching” mechanism, which also directed us to synthesize a series of hematite hollow structures, including hollow dodecahedron and hollow ellipsoid. The concentration of phosphate was found to play a decisive role in the control of these hollow structures. 0.08 mM is the critical point for keeping the top facets of dodecahedral hematite particles while 0.2 mM is the upper limit for keeping the lateral facets. The magnetic properties of these synthesized hollow hematite structures were found to be closely associated with the structures. The synthesized tube-in-dodecahedral hematite particles exhibited excellent photocatalytic reactivity toward organic dyes.
- Published
- 2016
33. Corrigendum to 'Thermal induced BCN nanosheets evolution and its usage as metal-free catalyst in ethylbenzene dehydrogenation' [Appl. Surf. Sci. 422 (2017) 574–581]
- Author
-
Conghui Wang, Ruimin Ding, Liancheng Wang, Baoliang Lv, Jianghong Wu, and Zhenwei Zhang
- Subjects
Materials science ,General Physics and Astronomy ,Surfaces and Interfaces ,General Chemistry ,Condensed Matter Physics ,Ethylbenzene ,Surfaces, Coatings and Films ,Catalysis ,chemistry.chemical_compound ,Chemical engineering ,chemistry ,Metal free ,Thermal ,Dehydrogenation - Published
- 2020
34. Highly efficient oxidative desulfurization of dibenzothiophene using Ni modified MoO3 catalyst
- Author
-
Zhi Liu, Liancheng Wang, Baoliang Lv, Ying Cao, Ruimin Ding, and Huixiang Wang
- Subjects
010405 organic chemistry ,Process Chemistry and Technology ,chemistry.chemical_element ,010402 general chemistry ,01 natural sciences ,Sulfur ,Catalysis ,0104 chemical sciences ,Flue-gas desulfurization ,Chemical kinetics ,chemistry.chemical_compound ,Reaction rate constant ,Decalin ,chemistry ,Dibenzothiophene ,Lewis acids and bases ,Nuclear chemistry - Abstract
Ni modified MoO3 (Ni-MoO3) had been synthesized by a facile one-step hydrothermal technique and was used for oxidative desulfurization (ODS) of dibenzothiophene (DBT) in the decalin/acetonitrile biphasic system with H2O2 as oxidant, the effect of different operating conditions was investigated. Under the optimal reaction condition, Ni-MoO3 catalyst showed excellent ODS performance toward DBT, the highest sulfur removal efficiency can be up to 99.8% and sulfur content was wiped out from 5000 to 10 ppm, which is more effective than the recent reported MoO3-based catalysts. The reaction kinetics obeyed the pseudo-first-order equation with an apparent rate constant of 0.076 min−1, which is twice that of pure MoO3 (0.035 min−1). The ODS mechanism of DBT with Ni-MoO3 was explored by combining radical scavenger, FT-IR experiments and theoretical analysis, proving that surface oxygen vacancies and Lewis acid sites play important roles in the high-efficiency ODS reaction with Ni-MoO3 catalyst.
- Published
- 2020
35. Glucose-mediated template-free synthesis of hollow CuO microspheres
- Author
-
Ning Zhao, Biao Qin, Qingjie Wang, Min Kang, Hai Zhou, Baoliang Lv, and Dong Wu
- Subjects
Template free ,Morphology (linguistics) ,Chemistry ,General Chemical Engineering ,chemistry.chemical_element ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Copper nitrate ,Copper ,0104 chemical sciences ,Microsphere ,law.invention ,Nanomaterials ,Transition metal ,Chemical engineering ,law ,Calcination ,0210 nano-technology - Abstract
In this work, we demonstrated a facile template-free method for the preparation of hollow CuO microspheres via a conventional hydrothermal reaction. The hollow architecture formed directly during the hydrothermal treatment of copper nitrate and glucose, without the use of template, precipitant and calcination process. The effects of reaction time, reaction temperature and glucose concentration were investigated in detail. On the basis of experimental results, the formation of hollow CuO microspheres probably proceeded via self-assemble process and the subsequent Ostwald's ripening. This synthetic strategy strongly depended on the characteristics of copper nitrate, which made it could not extend to other copper salts and/or nitrates. Even though, glucose still showed efficient morphology controlling ability with respect to nanosized transitional metal oxides, which could be used for the controllable synthesis of nanomaterials.
- Published
- 2018
36. Restructuring of Co3O4particles from polycrystalline microspheres to single-crystalline polyhedra under the assistance of acetic acid
- Author
-
Hai Zhou, Baoliang Lv, Dong Wu, Yao Xu, and Liancheng Wang
- Subjects
Cuboctahedron ,Materials science ,Oxide ,Nanoparticle ,General Chemistry ,Condensed Matter Physics ,Microstructure ,Acetic acid ,chemistry.chemical_compound ,Crystallography ,chemistry ,Octahedron ,Nanocrystal ,General Materials Science ,Crystallite - Abstract
A series of single-crystalline Co3O4 nanoparticles with shapes of an octahedron, a corner-truncated octahedron, a cube, a corner-truncated cube and a cuboctahedron were obtained by restructuring polycrystalline Co3O4 microspheres under the assistance of acetic acid. It was proved that the ionization equilibrium of acetic acid in the reaction system played a crucial role in the restructuring process. Besides obtaining a series of intermediate Co3O4 nanocrystals, this strategy could also show the internal relationship between these structures. This acid assisted restructuring method provides us a new route to modify the microstructure of metal oxide particles.
- Published
- 2015
37. Synthesis of polycrystalline Co 3 O 4 nanowires with excellent ammonium perchlorate catalytic decomposition property
- Author
-
Yao Xu, Baoliang Lv, Dong Wu, and Hai Zhou
- Subjects
Materials science ,Mechanical Engineering ,Thermal decomposition ,Nanowire ,Nanoparticle ,Condensed Matter Physics ,Ammonium perchlorate ,chemistry.chemical_compound ,Crystallography ,chemistry ,Chemical engineering ,Mechanics of Materials ,Transmission electron microscopy ,General Materials Science ,Crystallite ,Vapor–liquid–solid method ,High-resolution transmission electron microscopy - Abstract
Co 3 O 4 nanowires, with the length of tens of micrometers and the width of several hundred nanometers, were produced by a hydrothermal treatment and a post-anneal process. X-ray diffraction (XRD) result showed that the Co 3 O 4 nanowires belong to cubic crystal system. Scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM) analysis indicated that the Co 3 O 4 nanowires, composed by single crystalline nanoparticles, were of polycrystalline nature. On the basis of time-dependent experiments, methanamide-assisted hydrolysis and subsequent dissolution–recrystallization process were used to explain the precursors' formation process of the polycrystalline Co 3 O 4 nanowires. The TGA experiments showed that the as-obtained Co 3 O 4 nanowires can catalyze the thermal decomposition of ammonium perchlorate (AP) effectively.
- Published
- 2014
38. Fabrication of Fe3O4@C core–shell nanotubes and their application as a lightweight microwave absorbent
- Author
-
Wanxi Li, Liancheng Wang, Guomin Li, Yao Xu, and Baoliang Lv
- Subjects
Fabrication ,Materials science ,business.industry ,General Chemical Engineering ,Reflection loss ,Impedance matching ,chemistry.chemical_element ,General Chemistry ,engineering.material ,Condensed Matter::Materials Science ,chemistry ,Coating ,engineering ,Optoelectronics ,Dielectric loss ,business ,Absorption (electromagnetic radiation) ,Carbon ,Microwave - Abstract
With the continuing growth in demand for the reduction of electromagnetic radiation, lightweight and highly efficient microwave absorbents are greatly needed. In this study, Fe3O4@C core–shell nanotubes, with Fe3O4 nanotubes as cores and carbon as shells, of about 10 nm thickness have been successfully synthesized. Coating Fe3O4 nanotubes with carbon shells effectively increased dielectric loss and improved impedance matching of the composites, resulting in enhanced microwave absorption performance. The effective absorption bandwidth, with reflection loss (RL) less than −10 dB, was up to 6 GHz when the thickness of the test sample was as little as 1.7 mm, as determined using a vector network analyzer. Possessing a very low density of 1.4 g cm−3 and good microwave absorption performance, the as-fabricated Fe3O4@C core–shell nanotubes can meet the multiple property requirements of microwave absorbents.
- Published
- 2014
39. A small sample stretcher for in-situ small angle X-ray scattering measurement
- Author
-
D. Li, Q. Han, B. Hou, Baoliang Lv, F. Xie, and Zhihong Li
- Subjects
In situ ,Materials science ,010308 nuclear & particles physics ,Tension (physics) ,Scattering ,Small-angle X-ray scattering ,Resolution (electron density) ,Analytical chemistry ,Synchrotron radiation ,Polyethylene ,01 natural sciences ,030218 nuclear medicine & medical imaging ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,chemistry ,0103 physical sciences ,High-density polyethylene ,Instrumentation ,Mathematical Physics - Abstract
A small sample stretcher for in-situ measurement of small angle X-ray scattering (SAXS) was developed, which consists of stretch, transmission, detection and control systems. The basic parameters of the stretcher are: tension ≥ 400 N, 3 mm/min ≤ stretching speed ≤ 50 mm/min, sample length ≤ 30 mm, stroke ≥ 80 mm, and resolution = 50 μm. The stretcher is compact and has low stretching speed and convenient remote control. It is suitable for in-situ SAXS measurements on stretching of carbon fibers, polyethylene and other samples. Such measurement were carried out with high density polyethylene (HDPE) on the SAXS instrument at the 1W2A station of Beijing Synchrotron Radiation Facility (BSRF). The result verified the effectiveness of the stretcher.
- Published
- 2019
40. Microwave-Assisted Solvothermal Synthesis of Ag–Si Codoped TiO2 Nanoparticles for Enhanced Visible Light Photocatalytic Activity
- Author
-
Shuhai Chen, Yao Xu, Baoliang Lv, and Dong Wu
- Subjects
Materials science ,Solvothermal synthesis ,Doping ,Biomedical Engineering ,Bioengineering ,General Chemistry ,Condensed Matter Physics ,chemistry.chemical_compound ,Crystallinity ,X-ray photoelectron spectroscopy ,chemistry ,Chemical engineering ,Rhodamine B ,Photocatalysis ,General Materials Science ,Particle size ,Visible spectrum - Abstract
Ag-Si codoped TiO2 nanoparticles were successfully synthesized via a rapid and energy frugal microwave-assisted solvothermal method. The obtained materials were characterized by XRD, BET, TEM, XPS, and UV-Vis DRS. These characterizations revealed that the obtained materials possessed good crystallinity, small particle size and large surface area. In this system, silicon could enter into the crystal lattice of TiO2, leading to smaller particle size and larger surface area compared to pure TiO2; silver dispersed on the surface of TiO2 particles, contributing to the visible light response and benefiting the efficient separation of photoelectrons and holes. Thus, the synthesized materials should achieve enhanced photoactivity under visible light irradiation, and that was evaluated by the decomposition of Rhodamine B in the aqueous solution. It was found that the Ag-Si codoped TiO2 photocatalyst exhibited higher photocatalytic activity compared with pure TiO2 and Ag or Si doped TiO2. The doping amount of the silver showed significant effect on the photocatalytic activity, and the optimal activity was achieved with Ag content of 1 mol%.
- Published
- 2013
41. Hydrothermal synthesis and characterization of NiS flower-like architectures
- Author
-
Hai Zhou, Dong Wu, Yuhan Sun, and Baoliang Lv
- Subjects
Ammonium bromide ,Materials science ,Thiocyanate ,General Chemical Engineering ,Nanotechnology ,Coercivity ,Hydrothermal circulation ,chemistry.chemical_compound ,Crystallography ,chemistry ,Hydrothermal synthesis ,General Materials Science ,Cage effect ,Texture (crystalline) ,Powder diffraction - Abstract
a b s t r a c t Under the influence of thiocyanate anions (SCN−) and cetyltrimethyl ammonium bromide (CTAB), NiS flower-like architectures were successfully synthesized by a one-step hydrothermal method. The syn- thesized flower-like architectures, with a multilayered and highly ordered texture, have diameters of several micrometers. X-ray powder diffraction (XRD) shows that the NiS flower-like architectures are rhombohedral crystalline. On the basis of condition-dependent experiments, the diffusion-limited aggre- gation (DLA) model and cage effect were used to explain the growth process of rhombohedral crystalline NiS flower-like architectures. Magnetic measurements showed that the coercivity (Hc) of the as-obtained NiS flower-like architectures was 102.14 Oe.
- Published
- 2012
42. Facile synthesis of Ni(OH)1.4(SO4)0.3 nanoribbons and their photocatalytic properties
- Author
-
Hai Zhou, Yuhan Sun, Baoliang Lv, and Dong Wu
- Subjects
Materials science ,Mechanical Engineering ,Metals and Alloys ,Nanotechnology ,Hydrothermal circulation ,chemistry.chemical_compound ,chemistry ,Mechanics of Materials ,Transmission electron microscopy ,Lattice plane ,Materials Chemistry ,Ultraviolet light ,Photocatalysis ,Methyl orange ,Physical chemistry ,High-resolution transmission electron microscopy ,Powder diffraction - Abstract
With the presence of SCN − anions, Ni(OH) 1.4 (SO 4 ) 0.3 nanoribbons have been successfully synthesized by one-step hydrothermal method. The synthesized nanoribbons are with width of several tens of nanometers and length of several tens of micrometers. X-ray powder diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM) analysis revealed that the products were mainly dominated by (0 0 2) lattice plane. On the basis of condition-dependent experiments, a recrystallization–oxidation-split growth mechanism was proposed to explain the formation process of the Ni(OH) 1.4 (SO 4 ) 0.3 nanoribbons. As-synthesized products showed a photocatalytic capability under the irradiation of ultraviolet light for the decomposition of methyl orange as a probe reaction.
- Published
- 2012
43. Morphology and magnetic properties of α-Fe2O3 particles prepared by octadecylamine-assisted hydrothermal method
- Author
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Dong Wu, Yuhan Sun, Baoliang Lv, and Zhong Liu
- Subjects
chemistry.chemical_classification ,Materials science ,Scanning electron microscope ,General Chemical Engineering ,Nucleation ,Nanoparticle ,Nanotechnology ,Coercivity ,Hydrothermal circulation ,Chemical engineering ,chemistry ,Transmission electron microscopy ,General Materials Science ,High-resolution transmission electron microscopy ,Alkyl - Abstract
α-Fe2O3 particles with various morphologies, including micro-doublesphere, tetrakaidecahedron and nanoparticles-aggregated micro-ellipsoid, were successfully synthesized via an octadecylamine-assisted hydrothermal method. The products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM). The results indicate that the presence of octadecylamine played a crucial role in morphology evolution by selective crystal adsorption. The protonated octadecylamine increased the pH value that accelerated nucleation, and the long alkyl groups of octadecylamine acted as an adsorption inhibitor to retard the growth of nanoparticles. The as-prepared α-Fe2O3 particles exhibited higher remanent magnetization and coercivity than other α-Fe2O3 particles of similar size. These properties should be attributed to the superstructure and the shape anisotropy of the synthesized particles.
- Published
- 2012
44. Preparation and Properties of Octadecahedral α‐Fe 2 O 3 Nanoparticles Enclosed by {104} and {112} Facets
- Author
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Zhi Liu, Dong Wu, Yao Xu, Yuhan Sun, and Baoliang Lv
- Subjects
Inorganic Chemistry ,Steric effects ,Formamide ,Range (particle radiation) ,Crystallography ,chemistry.chemical_compound ,Aspect ratio ,Chemistry ,α fe2o3 nanoparticles ,Selective adsorption ,Nanoparticle ,Nanotechnology ,Coercivity - Abstract
Octadecahedral alpha-Fe2O3 nanoparticles were hydrothermally synthesized in the presence of formamide. These octadecahedral alpha-Fe2O3 nanoparticles have a threefold axis and are enclosed by twelve dominant {112} facets and six {104} facets. In comparison with the {104} facets, the sterically less hindered {112} facets induced the selective adsorption of formamide more easily, which resulted in the gradual increase in the amount of {112} facets by decreasing the amount of {104} facets with increasing formamide. The coercivity (Hc) of these octadecahedral particles increased successively as the aspect ratio (c/a) increased. The sensing capability of these particles toward H2O2 was investigated, and the response currents of the particles dominated by {112} facets showed a linear relationship with a concentration of H2O2 in the range from 40 mu M to 6.66 mM in different stages. Octadecahedral alpha-Fe2O3 nanoparticles were hydrothermally synthesized in the presence of formamide. These octadecahedral alpha-Fe2O3 nanoparticles have a threefold axis and are enclosed by twelve dominant {112} facets and six {104} facets. In comparison with the {104} facets, the sterically less hindered {112} facets induced the selective adsorption of formamide more easily, which resulted in the gradual increase in the amount of {112} facets by decreasing the amount of {104} facets with increasing formamide. The coercivity (Hc) of these octadecahedral particles increased successively as the aspect ratio (c/a) increased. The sensing capability of these particles toward H2O2 was investigated, and the response currents of the particles dominated by {112} facets showed a linear relationship with a concentration of H2O2 in the range from 40 mu M to 6.66 mM in different stages.
- Published
- 2012
45. Electron beam induced structural evolution in Fe3O4\SiO2 particles: A new route to obtain movable core structures
- Author
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Yao Xu, Dong Wu, Yuhan Sun, and Baoliang Lv
- Subjects
Nanostructure ,Materials science ,Mechanical Engineering ,Nanotechnology ,Condensed Matter Physics ,Evaporation (deposition) ,Molecular physics ,Amorphous solid ,chemistry.chemical_compound ,chemistry ,Mechanics of Materials ,Transmission electron microscopy ,Electron beam processing ,General Materials Science ,Irradiation ,Electron beam-induced deposition ,Ethylene glycol - Abstract
SiO2 hollow spheres with movable Fe3O4 core were obtained by exposing the pre-synthesized Fe3O4\SiO2 particles (with an adsorption interlayer of ethylene glycol) under the irradiation of electron beam inside transmission electron micrograph (TEM). In the formation process, the evaporation of adsorbed ethylene glycol and the evolution of amorphous SiO2 layer played important roles, and that should be attributed to the high temperature and trapped charges induced by the irradiation of electron beam. This work provided a new route to obtain particles with movable core structure and extended the applications of electron beam.
- Published
- 2011
46. Synthesis of Fe3O4\SiO2\Ag nanoparticles and its application in surface-enhanced Raman scattering
- Author
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Hong Tian, Yuhan Sun, Baoliang Lv, Dong Wu, and Yao Xu
- Subjects
Materials science ,Composite number ,Shell (structure) ,Analytical chemistry ,Ag nanoparticles ,Condensed Matter Physics ,Electronic, Optical and Magnetic Materials ,Inorganic Chemistry ,symbols.namesake ,chemistry.chemical_compound ,chemistry ,Materials Chemistry ,Ceramics and Composites ,symbols ,Rhodamine B ,Molecule ,Ultrasonic sensor ,Physical and Theoretical Chemistry ,Layer (electronics) ,Raman scattering - Abstract
To obtain a recyclable surface-enhanced Raman scattering (SERS) material, we developed a composite of Fe3O4\SiO2\Ag with core\shell\particles structure. The designed particles were synthesized via an ultrasonic route. The Raman scattering signal of Fe3O4 could be shielded by increasing the thickness of the SiO2 layer to 60 nm. Dye rhodamine B (RB) was chosen as probe molecule to test the SERS effect of the synthesized Fe3O4\SiO2\Ag particles. On the synthesized Fe3O4\SiO2\Ag particles, the characteristic Raman bands of RB could be observed when the RB solution was diluted to 5 ppm (1×10−5 M). Furthermore, the synthesized particles could keep their efficiency till four cycles.
- Published
- 2010
47. Preparation, characterization and combustion properties of Zr/ZrH2 particles coated with α-FeOOH crystal grains
- Author
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Yao Xu, Dong Wu, Yuhan Sun, Baoliang Lv, and Bo Hou
- Subjects
chemistry.chemical_classification ,Acicular ,Materials science ,Scanning electron microscope ,General Chemical Engineering ,Diffusion ,Nucleation ,Mineralogy ,Polymer ,Combustion ,Crystal ,symbols.namesake ,chemistry ,Chemical engineering ,symbols ,General Materials Science ,Raman spectroscopy - Abstract
Zr/ZrH 2 particles with irregular morphologies and broad size distribution were uniformly coated with acicular α-FeOOH crystal grains via a facile route without using polymers or surfactants. The as-synthesized material was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), UV–vis diffusion reflection (UV–vis) and Raman spectrometry. Based on these characterizations, the synthesis mechanism was explained in terms of combined heterogeneous nucleation and solid state transformation reaction. The presence of α-FeOOH coating greatly changed the combustion behavior of Zr/ZrH 2 particles: the combustion lasting time decreased from 32 s for un-coated Zr/ZrH 2 particles to 0.2 s for coated particles while the maximum temperature in the combustion process increased from 1510 °C to 2036 °C.
- Published
- 2009
48. Preparation and properties of magnetic iron oxide nanotubes
- Author
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Yao Xu, Dong Wu, Yuhan Sun, and Baoliang Lv
- Subjects
Nanotube ,Materials science ,General Chemical Engineering ,Iron oxide ,Maghemite ,Sintering ,Nanotechnology ,engineering.material ,Coercivity ,Hematite ,chemistry.chemical_compound ,Chemical engineering ,chemistry ,Phase (matter) ,visual_art ,engineering ,visual_art.visual_art_medium ,General Materials Science ,Magnetite - Abstract
Magnetite (Fe3O4) nanotubes were prepared by reducing synthesized hematite (α-Fe2O3) nanotubes in 5% H2+95% Ar atmosphere, and then maghemite (γ-Fe2O3) nanotubes were obtained by re-oxidizing the Fe3O4 nanotubes. The nanotube structure was kept from collapsing or sintering throughout the high temperature reducing and re-oxidizing processes. The coercivities of the Fe3O4 and γ-Fe2O3 nanotubes synthesized were found to be 340.22 Oe and 342.23 Oe, respectively, both higher than other nanostructures with the same phase and of similar size. Both adsorbed phosphate and the nanotube structure are considered responsible for this high coercivity.
- Published
- 2008
49. Preparation and combustion properties of α-Fe2O3 coated Zr particles
- Author
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Bo Hou, Yao Xu, Dong Wu, Yuhan Sun, and Baoliang Lv
- Subjects
chemistry.chemical_classification ,Zirconium ,Materials science ,Scanning electron microscope ,Mechanical Engineering ,Composite number ,Nucleation ,chemistry.chemical_element ,Polymer ,Condensed Matter Physics ,Combustion ,Crystal ,symbols.namesake ,Crystallography ,chemistry ,Chemical engineering ,Mechanics of Materials ,symbols ,General Materials Science ,Raman spectroscopy - Abstract
Zirconium particles with irregular morphology and broad size distribution were uniformly coated by spherical α-Fe2O3 crystal grain via a facile route without polymer or surfactant as directing agents. The synthesized α-Fe2O3/Zr composite particles were characterized by X-ray diffraction, scanning electron microscopy, energy dispersion X-ray, UV–vis spectroscopy and Raman spectroscopy. The synthesis mechanism could be explained by cooperated heterogeneous nucleation and solid state transformation reaction. The combustion properties of α-Fe2O3/Zr composite particles were investigated. Compared with Zr particles, the combustion lasting time decreased from 16 s of Zr particles to 0.13 s of α-Fe2O3/Zr composite particles, and the top point of temperature reached in combustion increased from 2004 °C of Zr particles to 2378 °C of α-Fe2O3/Zr particles.
- Published
- 2008
50. Fe-quinoline complexes sensitized Si-doped TiO2 with enhanced visible light photocatalytic activity
- Author
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Yao Xu, Baoliang Lv, and Shuhai Chen
- Subjects
Aqueous solution ,Materials science ,Mechanical Engineering ,Quinoline ,Nanoparticle ,Condensed Matter Physics ,Photochemistry ,Rhodamine ,chemistry.chemical_compound ,chemistry ,Mechanics of Materials ,Rhodamine B ,Photocatalysis ,General Materials Science ,Absorption (electromagnetic radiation) ,Visible spectrum - Abstract
Si-doped TiO2 nanoparticles were prepared via a solvothermal method and were sensitized by the Fe-quinoline complexes (HQSI) to improve the visible light photocatalytic activity. The used HQSI had a narrow band gap of 1.54 eV and showed strong visible light absorption. HQSI can transfer photoelectrons to the conduction band of TiO2 and be regenerated by the electron injection from Rhodamine B. After sensitization, the Si-doped TiO2 exhibited stronger absorption in the visible region and showed higher visible-light photocatalytic activity for the degradation of Rhodamine B in an aqueous solution than the simple Si-doped TiO2 and sensitized commercial TiO2.
- Published
- 2012
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