Search

The exploration of high-performance hydrogen evolution reaction (HER) catalysts is conducive to the development of clean hydrogen energy, yet still remains a challenge. Herein, we rapidly synthesize the Mo2C/MoS2 heterostructure on carbon paper (Mo2C/MoS2–CP) via carbothermal shock in only two seconds. The construction of the Mo2C/MoS2 heterostructure regulates the electronic structure of the Mo site and facilitates charge transfer during the HER process. Moreover, the catalyst exhibits enhanced hydrophilicity and aerophobicity, facilitating optimal electrolyte–catalyst interaction and efficient hydrogen bubble detachment for accelerated mass transfer. Consequently, Mo2C/MoS2–CP exhibits superior intrinsic alkaline HER activity, and excellent stability for 100 h. This finding provides a novel insight into the development of outstanding HER catalysts. [ABSTRACT FROM AUTHOR]

In the present work, exfoliated graphitic carbon nitride (g‐CN) is immobilized on carbon paper substrates by a simple electrophoretic route, and subsequently decorated with ultra‐low amounts (≈μg/cm2) of Pt nanoparticles (NPs) by cold plasma sputtering. Optimization of preparative conditions allowed a fine tuning of Pt NPs size, loading and distribution and thus a controlled tailoring of g‐CN/Pt interfacial interactions. Modulation of such features yielded g‐CN‐Pt‐based anode materials with appealing activity and stability towards the ethanol oxidation reaction (EOR) in alkaline aqueous solutions, as revealed by electrochemical tests both in the dark and under irradiation. The present results provide new insights on the design of nano‐engineered heterocomposites featuring improved performances thanks to Pt coupling with g‐CN, a low‐cost and environmentally friendly visible light‐active semiconductor. Overall, this work might open attractive avenues for the generation of green hydrogen via aqueous ethanol electrolysis and the photo‐promoted alcohol electrooxidation in fuel cells. [ABSTRACT FROM AUTHOR]

Molybdenum sulphide (2D-MoS 2) promises great potential as a hydrogen evolution (HER) catalyst, especially, when combined with conductive carbon supports like graphene oxide (GO) and carbon nanotubes (CNT). However, the hydrophobic nature of these carbon supports limits the catalytic potential of MoS 2. To overcome this, we introduced hydrophilic Nickel Boride (Ni 2 B) into GO/CNT electrodes (Ni 2 B-GO/CNT), enhancing wettability (Contact angle-25.3°) and HER activity. By hydrothermally depositing MoS 2 onto the hydrophilic Ni 2 B-GO/CNT electrode, we fabricated a self-supporting MoS 2 @Ni 2 B-GO/CNT electrode. The MoS 2 deposition led to the formation of MoS 2 @Ni 2 B-GO/CNT heterostructure with multiple interfaces, favoring interfacial electronic redistribution (XPS) to significantly improve the HER activity. Thus, the proposed MoS 2 @Ni 2 B-GO/CNT electrode exhibited an excellent durability of 100 h (97%) and an overpotential of 224 mV at 10 mA cm−2 in acidic medium. [Display omitted] • Hydrothermal growth of MoS 2 on Ni 2 B-GO/CNT to form a self-supporting electrode. • Hydrophilic Ni 2 B was incorporated into the GO/CNT matrix to enhance electrode wettability. • Enhanced HER catalytic activity from a heterostructure of MoS 2 with Ni 2 B, GO and CNT. • Excellent durability of MoS 2 @ Ni 2 B-GO/CNT was achieved for 100 h in acidic medium. [ABSTRACT FROM AUTHOR]

Nanorod structures exhibit a high surface-to-volume ratio, enhancing the accessibility of electrolyte ions to the electrode surface and providing an abundance of active sites for improved electrochemical sensing performance. In this study, tetragonal α-MnO2 with a large K+-embedded tunnel structure, directly grown on microfibrous carbon paper to form densely packed nanorod arrays, is investigated as an electrocatalytic material for non-enzymatic glucose sensing. The MnO2 nanorods electrode demonstrates outstanding catalytic activity for glucose oxidation, showcasing a high sensitivity of 143.82 µA cm−2 mM−1 within the linear range from 0.01 to 15 mM, with a limit of detection (LOD) of 0.282 mM specifically for glucose molecules. Importantly, the MnO2 nanorods electrode exhibits excellent selectivity towards glucose over ascorbic acid and uric acid, which is crucial for accurate glucose detection in complex samples. For comparison, a gold electrode shows a lower sensitivity of 52.48 µA cm−2 mM−1 within a linear range from 1 to 10 mM. These findings underscore the superior performance of the MnO2 nanorods electrode in both sensitivity and selectivity, offering significant potential for advancing electrochemical sensors and bioanalytical techniques for glucose monitoring in physiological and clinical settings. [ABSTRACT FROM AUTHOR]

In this study, the microstructure of carbon fiber paper is modified through H 3 PO 4 etching to enhance the electrolyzer performance. The effects of different H 3 PO 4 concentrations and different soaking times on the hydrogen evolution reaction are firstly investigated. The electrochemical test results show that the best performance of etched electrodes is achieved at a H 3 PO 4 concentration of 1 M and a soaking time of 12 h, with a significant reduction in charge transfer resistance and overpotential. Subsequently, to explore the change mechanism in electrochemical properties, the microstructure of the carbon paper is investigated using Scanning Electron Microscope (SEM) and Mercury Intrusion Porosimetry (MIP) tests, which show uniformly distributed micropores appear on the surface of the carbon fibers after etching, and the porosity increases from 0.74 to 0.8. Brunauer-Emmett-Teller (BET) tests show that the specific surface area of the carbon paper increases from 0.72 m2/g to 4.06 m2/g, which effectively increases the interfacial contact area between the catalyst layer and the liquid gas diffusion layer. Furthermore, a 3D multi-physics model is established to further elucidate the impact mechanism of changes in porosity, conductivity, and active specific surface area on the performance of anion exchange membrane electrolyzer, with changes in active specific surface area having the greatest effect. • Microporous structure of the carbon paper LGDL is modified by etching. • The etching method effectively improves the performance of AEMEL. • The increase in specific surface area and porosity greatly reduces the resistance. • Numerical modeling to analyze the impact of microscopic parameters on AEMEL. • LGDL with high specific surface area has a positive effect on AEMEL's development. [ABSTRACT FROM AUTHOR]

Developing highly efficient and stable electrocatalysts for urea electro-oxidation reactions (UORs) will improve wastewater treatment and energy conversion. A low-cost cobalt sulfide-anchored nickel sulfide electrode (CoS/Ni3S2@CP) was synthesized by electrodeposition in DMSO solutions and found to be highly effective and long-lasting. The morphology and composition of catalyst surfaces were examined using comprehensive physicochemical and electrochemical characterization. Specifically, CoS/Ni3S2@CP electrodes require a potential of 1.52 volts for a 50 mA/cm2 current, confirming CoS in the heterointerface CoS/Ni3S2@CP catalyst. Further, the optimized CoS/Ni3S2@CP catalyst shows a decrease of 100 mV in the onset potential (1.32 VRHE) for UORs compared to bare Ni3S2@CP catalysts (1.42 VRHE), demonstrating much greater performance of UORs. As compared to Ni3S2@CP, CoS/Ni3S2@CP exhibits twofold greater UOR efficiency as a result of a larger electroactive surface area. The results obtained indicate that the synthetic CoS/Ni3S2@CP catalyst may be a favorable electrode material for managing urea-rich wastewater and generating H2. [ABSTRACT FROM AUTHOR]

A crucial factor in advancing the broad utilization of electrocatalytic hydrogen evolution reaction (HER) is the development of efficient catalysts with sufficient active sites. Herein, a hydrothermal approach is utilized to fabricate helical chain stacked two‐dimensional (2D) tellurium (Te) nanoflakes, whose HER performance hasn't been systematically studied yet. It is found that Te nanoflakes transferred on carbon fiber paper (CFP) exhibit impressive HER properties and show a load dependence. The overpotential required for HER is significantly reduced to 279 mV under a load condition of 0.86 mg cm−2 at a current density of 10 mA cm−2. Density functional theory (DFT) calculations are further systematically carried out on Te catalytic sites along the helical chain at [0001] direction with a threefold screw symmetry. It is found that the Gibbs free energy of adsorbed hydrogen atom (ΔGH*) on Te sites is significantly lower than that of molybdenum disulfide (MoS2). Besides, the active sites based on surface atom density calculation reveal that Te provides more adsorption sites than layered MoS2. The decreased adsorption energy and efficient adsorption sites in Te may highlight the promising application of elemental crystal Te in electrocatalytic hydrogen production and pave the way for developing new types of electrocatalysts. [ABSTRACT FROM AUTHOR]

This paper focuses on proton exchange membrane fuel cell (PEMFC) operation at current densities in the order of 6 A/cm2. Such high current densities are conceivable when the traditional carbon fiber papers are replaced with perforated metal plates as the gas diffusion layer to enhance waste heat removal, and at the same time the relative humidity inside the fuel cell is kept below 100% by applying appropriate operating conditions as was found in previous one-dimensional modeling work. In the current paper, we applied a three-dimensional, multi-phase computational fluid dynamics model based on Ansys-CFX to obtain additional insight into the underlying physics. The calculated pressure drops are in very good agreement with previous one-dimensional modeling work, and the current densities in all case studies are in the order of 5–6 A/cm2, but different from the previous one-dimensional study, the results suggest that the relative humidity is very close to 100% throughout the entire channel length when the inlet relative humidity is 100%, ensuring best hydration cell conditions and hence best performance. Importantly, the model results suggest that fuel cell performance at a high current density in conjunction with relatively low stoichiometric flow ratios around 1.5–2 is possible. [ABSTRACT FROM AUTHOR]

Efficient and sustainable energy storage remains a critical challenge in the advancement of energy technologies. This study presents the fabrication and electrochemical evaluation of a self-supporting electrode material composed of MnO2 nanorods grown directly on a carbon paper and carbon nanotube (CNT) substrate using a hydrothermal method. The resulting CNT/MnO2 electrodes exhibit a unique structural architecture with a high surface area and a three-dimensional hierarchical arrangement, contributing to a substantial electrochemical surface area. Electrochemical testing reveals remarkable performance characteristics, including a specific capacitance of up to 316.5 F/g, which is 11 times greater than that of conventional CP/MnO2 electrodes. Moreover, the CNT/MnO2 electrodes demonstrate outstanding retention capacity, exhibiting a remarkable 165% increase over 10,000 cycles. Symmetric supercapacitor devices utilizing CNT/MnO2 electrodes maintain a large voltage window of 3 V and a specific capacitance as high as 200 F/g. These results underscore the potential of free-standing CNT/MnO2 electrodes to advance the development of high-performance supercapacitors, which can be crucial for efficient and sustainable energy storage solutions in various industrial and manufacturing applications. [ABSTRACT FROM AUTHOR]

Direct air capture (DAC) is a sustainable technology to alleviate the greenhouse effect and a reliable pathway to acquire inexhaustible CO2 for the production of costly chemicals and energy products. Current DAC technologies with amine‐related sorbents rely on chemisorption, while they consume intensive energy for CO2 release and sorbent regeneration by heating. Developing new DAC processes with weak, reversible adsorption can substantially reduce the regeneration energies. Herein, the design of CO2 breathing paper (CBP) is demonstrated toward spontaneous CO2 extraction from ambient air and solar‐driven regeneration. The CBP is fabricated by coupling 2‐ethyl‐4‐methylimidazole to carbon nanotube paper on the basis of density functional theory calculations. At ambient conditions, CBP spontaneously captures atmospheric CO2 with a capacity of 0.14–1.75 mmol g–1 at 0–35 °C through non‐covalent electrostatic interaction. Upon exposure to sunlight, all adsorbed CO2 can be released and converted to concentrated gas for storage. Attractively, the efficiency of solar‐driven CO2 release is much higher than the traditional temperature‐swing method owing to the IR sensitivity of CO2. Besides the reversibility, the mild conditions also ensure the durability of CBP. These findings suggest that the CBP is a promising candidate for cost‐effective DAC. [ABSTRACT FROM AUTHOR]

The electrochemical carbon dioxide reduction reaction (CO2RR) holds substantial promise for producing high‐value chemicals and fuels, drawing significant attention from both academia and industry. This work proposes an in‐situ electrodeposition method to prepare indium‐doped copper (Cu)‐based catalysts on carbon paper (Cu100Inx−CP, x=3.9, 4.5, 4.8, 5.1, and 7.6, denoting the molar ratio of In to Cu in the catalyst.). The catalysts Cu100Inx−CP were used for CO2RR to produce multi‐carbon (C2+) products. Characterization results showed that In was highly dispersed in the Cu particles at x<5.1. The Cu100In5.1−CP (containing 0.95 wt % In based on Cu) was very efficient for electrocatalytic CO2RR. The in‐situ Raman spectroscopy showed that Cu100In5.1−CP enhanced *CO intermediate adsorption and promoted the production of C2+ products due to the synergistic effect between In and Cu. In doping could suppress HER, enhanced *CO intermediate adsorption, and C−C coupling for the production of C2+ products in CO2RR. [ABSTRACT FROM AUTHOR]

Active and stable electrocatalysts with low precious metal loading is essential for the widespread application of proton-exchange water electrolyzers. Construction of core-shell structure offers the possibility to achieve high catalytic activity and good stability, and simultaneously to reduce the precious-metal loading. Here, Co 3 O 4 -core IrO x -shell nanoparticles (Co 3 O 4 @IrO x) are synthesized by immersing the solvothermal synthesized Co 3 O 4 in alkaline IrCl 3 aqueous solution, followed by annealing at 350 °C for 2 h. The Co 3 O 4 @IrO x -10, which exhibits the highest oxygen evolution reaction (OER) activity when supported on carbon paper, are 9.76 nm in average diameter, and the surface IrO x layer is about 0.97 nm. Only 337 mV overpotentials are required to reach the 10 mA cm−2 OER current densities in 0.1 M HClO 4 for the Co 3 O 4 @IrO x -10, with the mass activity reaches 1.44 A mg−1 Ir at 370 mV overpotentials. The high OER activity is originated from the increased number of active sites and more facile kinetics, demonstrated by the lower charge transfer resistance, lower activation energy and lower Tafel slope values. The optimized adsorption energy of OH* intermediates caused by the electronic interaction between the Co 3 O 4 core and the IrO x shell facilitates the OER kinetics. The Co 3 O 4 @IrO x -10 supported on carbon paper is stable towards the long-term OER in acid, and the IrO x shell layer can effectively protect the Co 3 O 4 core. The Co 3 O 4 @IrO x -10 are promising candidates as the low precious metal electrocatalysts for OER in acid. • The Co 3 O 4 @IrO x -y core-shell nanoparticles are synthesized successfully. • The core-shell structure enhanced the activity and stability of the catalyst. • The core-shell structure significantly reduced the amount of IrO x addition. • The electron interaction between Co 3 O 4 and IrO x optimizes the adsorption energy of OH* intermediates. [ABSTRACT FROM AUTHOR]

Metal ferrite (MFO) M2+Fe2O4 (M2+ = Mn, Co, Ni, and Zn) nanocrystals (NCs) with a controlled size of ∼4 nm were synthesized using stearic acid as the capping agent via a facile solvothermal method. The as-synthesized MnFe2O4 (MnFO), CoFe2O4 (CoFO), NiFe2O4 (NiFO), and ZnFe2O4 (ZnFO) NCs were characterized by XRD, FT-IR, Raman, XPS, TGA, TEM, and HRTEM analyses. The electrocatalytic oxygen evolution reaction (OER) is significant for future renewable energy to produce pure hydrogen (H2) fuels through H2O splitting. However, because of the complex proton-coupled multielectron transfer process, it is kinetically quite challenging. Fe-containing transition metal-based electrocatalysts are well studied since it has been observed that Fe has a significant role in enhancing OER activity. It is well-known that the size and shape of the Fe/ferrite-based nanoelectrocatalyst play a vital role in electrocatalysis reactions. However, it is also critical to understand the effect of other earth-abundant and cost-effective transition metal ions (e.g., Mn, Co, Ni, and Zn) combined with Fe/ferrite NC-based OER electrocatalytic reactions while keeping the size of NCs constant and compare their electrocatalytic properties toward the development of advanced nanoelectrocatalysts, which is rarely studied to the best of the authors knowledge. Therefore, herein, the electrocatalytic properties for OER were examined by using the as-synthesized MnFO, CoFO, NiFO, and ZnFO NCs to understand the effect of metal ions (Mn, Co, Ni, and Zn) on the Fe-based nanoelectrocatalysts by keeping the size of the nanoelectrocatalysts constant at ∼4 nm. Additionally, the influence of different substrates, e.g., carbon paper (CP) and nickel foam (NF), on the electrocatalytic activity of MFO (MnFO, CoFO, NiFO, and ZnFO) NCs was also compared. Interestingly, as an OER nanoelectrocatalyst, the CoFO NCs on the CP substrate show better electrochemical OER activity than other MFO NCs, with a Tafel slope value of 49.4 mV dec–1, an ECSA of 112 cm2, and a long-term stability of 24 h, which is comparatively higher than the other as-synthesized MFO NCs. On the other hand, MnFO NCs on the NF substrate show better electrochemical OER activity than the other as-synthesized MFO NCs. Therefore, this work highlights the effect of the substrate and the influence of transition metals, e.g., Mn, Co, Ni, and Zn, on size-controlled Fe-based nanoelectrocatalysts toward developing advanced OER electrocatalysts. [ABSTRACT FROM AUTHOR]

Baicalin (Bn) is one of the flavonoids with various biological activities, and its accurate determination is of great significance to clinical medicine. The new "MOF-on-MOF" materials have a broad application prospect. ZIF-67 and MIL-101(Fe) are typical metal–organic frame (MOF) materials, which have the advantages of flexible structure, large specific surface area, large porosity, and adjustable pore size. In this paper, a disposable and sensitive Bn electrochemical sensor based on ZIF-67/MIL-101(Fe) composite modified carbon paper (CP) electrode was developed for the first time. The sensing nanomaterials were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction spectroscopy (XRD), and X-ray photoelectron spectroscopy (XPS). Cyclic voltammetry (CV) was used to evaluate the electrochemical behavior of Bn on different modified electrodes. The results showed that ZIF-67/MIL-101(Fe)/CP exhibited a well-defined redox peak compared with bare CP, ZIF-67/CP, and MIL-101(Fe)/CP, which was attributed to the synergistic effect of ZIF-67 and MIL-101(Fe). Under optimal conditions, the electrochemical sensor was able to quantify Bn in the ranges of 0.01 ~ 3 µM and 3 ~ 6 µM with a detection limit (LOD) as low as 0.009 µM (S/N = 3). In addition, the sensor was successfully used for the quantitative analysis of Bn in Dual yellow oral liquid with reliable results. [ABSTRACT FROM AUTHOR]

Nitrogen doped graphene nanowall(s) deposited on carbon paper is employed in sequestration of trace-level plutonium from aqueous solution using batch adsorption technique. Surface and structural characteristics of the sorbent are studied using SEM and Raman spectroscopy, respectively. Radiometric α-counting of the supernatant solution showed > 90% sorption at pH > 7. Visual Minteq modelling revealed that Pu(OH)4 species is responsible for high sorption. Freundlich model evolved as the best fit, implying multilayer deposition on a heterogeneous surface as the mechanism of sorption. The combination of 10 M HNO3 and EDTA resulted in 75% desorption. The results are promising for the sequestration of trace-level plutonium. [ABSTRACT FROM AUTHOR]

An electrochemical sensing platform based on in-situ acetylene black (AB) template growth ZIF-8 for trace catechin detection in green tea was proposed. Here, the ZIF-8/AB/carbon paper (CP) electrode was constructed by two-step in-situ growth method and hydrothermal method. The characterization showed that AB molecule was well distributed in ZIF-8 pore with large surface area. ZIF-8/AB/CP electrode showed good electrochemical performance for catechin detection, which benefited from the ZIF-8 with larger surface and AB with excellent conductivity. The results showed that ZIF-8/AB/CP electrode was linear in the range of 0.01–200 µM, and the low detection limit for catechin detection was 43.7 nM. ZIF-8/AB/CP also had good reproducibility, anti-interference ability and stability. In addition, the sensor achieved hight-recovery and accuracy in detecting catechin in green tea. As far as we know, our work first reported that ZIF-8/AB composite was synthesized by in-situ growth method as an electrochemical sensing material for the detection of catechin in green tea, which will provide some theoretical analysis and experimental experience for designing and developing electrochemical sensor for the analysis of trace catechin. [ABSTRACT FROM AUTHOR]

Copyright of China Pulp & Paper is the property of China Pulp & Paper Magazines Publisher and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This mini‐review summarises and discusses recent findings form the literature on the degradation of carbon‐based electrodes for vanadium redox flow batteries (VRFBs). It becomes evident that the focus of current investigations is on carbon paper, carbon felt and graphite felt electrodes, which is understandable from a practical point of view. However, the structural complexity of these materials often prohibits doubtless attribution of observed performance reduction (or increase) to changes in the electrode materials. Among the discussed major causes for degradation are formation or change of surface functional groups, changes in the carbon sp2/sp3 ratio, intercalation of ions as well as formation of inhibiting adsorbates. In order to gain deeper insight into the changes of carbon electrodes in VRFBs under relevant operation conditions, the authors suggest reducing complexity of the investigated materials and applying in situ‐studies under well‐defined and controllable conditions on model electrodes. These studies then should be extended towards more practical systems and may finally help to reduce degradation phenomena including enhanced overvoltages and thus could improve cycling and energy efficiency as well as long‐term stability of vanadium redox flow batteries. [ABSTRACT FROM AUTHOR]

The sulfuric acid-doping polyaniline (H-PANI-HSO4) are applied to conduct the electrochemical measurement and simulation calculation to investigate the capacitance, electronic structure and energy band properties. The H-PANI-HSO4 growing on graphite carbon paper (H-PANI-HSO4/GCP) is applied as an electroactive electrode to investigate electrochemical properties. The Faradaic capacitance of H-PANI-HSO4/GCP electrode is ascribed to the reversible redox reaction of bisulfate anion doping/dedoping protonated PANI (H-PANI). Cyclic voltammetry measurement at a scan rate of 5mVs−1 determines an equivalent mean response current of 0.64Ag−1 and a capacitance of 128.35Fg−1. Galvanostatic charge–discharge measurement determines specific capacitance from 129.06 to 116.88Fg−1 at current densities from 0.5 to 2.5Ag−1. Cyclic voltammetry-based capacitance at equivalent current density of 0.64Ag−1 is in accordance with galvanostatic charge–discharge-based capacitance at the current density of 0.57Ag−1. Electrochemical impedance spectrum measurements indicate that H-PANI-HSO4/GCP exhibits lower charge-transfer resistance, much lower Warburg resistance, higher quasicapacitance than H-PANI-HSO4 to approaching ideal capacitor. Density functional theory calculations indicate that H-PANI-HSO4 has a higher density of states (10.6 electron/eV) and lower bandgap energy (0.481eV) than H-PANI (5.24 electron/eV, 1.449eV), indicating its enhanced electronic conductivity. The electronic bandgap energy is accordingly decreased from 0.263eV for H-PANI-HSO4/GCP to 0 for H-PANI-HSO4/GCP. Electrochemical measurement and simulation calculation investigation proves that H-PANI-HSO4/GCP electrode with anion-doped and protonated state exhibits higher electronic conductivity and capacitance performance to act as superior electroactive material. [ABSTRACT FROM AUTHOR]

Various electrocatalysts are extensively examined for their ability to selectively produce desired products by electrochemical CO2 reduction reaction (CO2RR). However, an efficient CO2RR electrocatalyst doesn't ensure an effective co‐catalyst on the semiconductor surface for photoelectrochemical CO2RR. Herein, Bi2S3 nanorods are synthesized and electrochemically reduced to Bi nanoplates that adhere to the substrates for application in the electrochemical and photoelectrochemical CO2RR. Compared with commercial‐Bi, the Bi2S3‐derived Bi (S‐Bi) nanoplates on carbon paper exhibit superior electrocatalytic activity and selectivity for formate (HCOO−) in the electrochemical CO2RR, achieving a Faradaic efficiency exceeding 93%, with minimal H2 production over a wide potential range. This highly selective S‐Bi catalyst is being employed on the Si photocathode to investigate the behavior of electrocatalysts during photoelectrochemical CO2RR. The strong adhesion of the S‐Bi nanoplates to the Si nanowire substrate and their unique catalytic properties afford exceptional activity and selectivity for HCOO− under simulated solar irradiation. The selectivity observed in electrochemical CO2RR using the S‐Bi catalyst correlates with that seen in the photoelectrochemical CO2RR system. Combined pulsed potential methods and theoretical analyses reveal stabilization of the OCHO* intermediate on the S‐Bi catalyst under specific conditions, which is critical for developing efficient catalysts for CO2‐to‐HCOO− conversion. [ABSTRACT FROM AUTHOR]

The plasma treatment method, which is a simple and ecologically benign procedure, is used to treat the gas diffusion layer (GDL) surface for proton exchange membrane fuel cell (PEMFC) application. The surface plasma treatment greatly aids in the uniform in situ growth of platinum (Pt) nanowires on the GDL surface to fabricate gas diffusion electrodes (GDEs). Helium (He) and nitrogen (N 2) are used, and the outcomes from utilising each gas independently are compared at four different durations between 30 s, 60 s, 90 s, and 120 s. Membrane Electrode Assemblies (MEAs) are fabricated with the as-prepared GDEs and tested in H 2 /air PEMFC single cells. The testing results show the nitrogen plasma applied to the GDE surface for 60 s produces the best power performance with a current density of 1372.7 mA/cm2 at 0.6V. [Display omitted] • The surface of the gas diffusion layer (GDL) was activated using the plasma treatment method. • Carbon papers, whose surface was activated by He and N2 in plasma, were immersed in the prepared Pt solution. • Pt nanowires were allowed to grow on carbon papers. • Membrane Electrode Assemblies (MEAs) were created using as-prepared GDEs as the cathode and purchased GDL as the anode. • As a result of testing the created MEAs, it was seen that the GDL surface activated using N 2 plasma gave better results. [ABSTRACT FROM AUTHOR]

The increasing global water pollution leads to the need for urgent development of rapid and accurate water quality monitoring methods. Microbial fuel cells (MFCs) have emerged as real-time biosensors for biochemical oxygen demand (BOD), but they grapple with several challenges, including issues related to reproducibility, operational stability, and cost-effectiveness. These challenges are substantially shaped by the selection of an appropriate air-breathing cathode. Previous studies indicated a critical influence of the cathode on both the enduring electrochemical performance of MFCs and the taxonomic diversity at the electroactive anode. However, the effect of different gas diffusion electrodes (GDE) on 3D-printed single-chamber MFCs for BOD biosensing application and its effect on the bioelectroactive anode was not investigated before. Our study focuses on comparing GDE cathode materials to enhance MFC performance for precise and rapid BOD analysis in wastewater. We examined for over 120 days two Pt-coated air-breathing cathodes with distinct carbonaceous gas diffusion layers (GDLs) and catalyst layers (CLs): cost-effective carbon paper (CP) with hand-coated CL and more expensive woven carbon cloth (CC) with CL pre-applied by the supplier. The results show significant differences in electrochemical characteristics and anodic biofilm composition between MFCs with CP and CC GDE cathodes. CP-MFCs exhibited lower sensitivity (16.6 C L mg−1 m−2) and a narrower dynamic range (25 to 600 mg L−1), attributed to biofouling-related degradation of the GDE. In contrast, CC-MFCs demonstrated superior performance with higher sensitivity (37.6 C L mg−1 m−2) and a broader dynamic range (25 to 800 mg L−1). In conclusion, our study underscores the pivotal role of cathode selection in 3D-printed MFC biosensors, influencing anodic biofilm enrichment time and overall BOD assessment performance. We recommend the use of cost-effective CP GDL with hand-coated CL for short-term MFC biosensor applications, while advocating for CC GDL supplied with CL as the preferred choice for long-term sensing implementations with enduring reliability. [ABSTRACT FROM AUTHOR]

Carbon emissions from the Yangtze River Economic Belt are an important element of China's carbon emission endeavor, and a study of its emission reduction pathway can provide a reference for the country's overall management of carbon emission reduction. From the perspective of energy consumption, this paper uses the carbon emission factor method to estimate the carbon emissions of the transportation industry in the Yangtze River Economic Belt during 2006–2020, based on the extended STIRPAT model, considering the influence of seven factors, i.e., population size, urbanization rate, GDP per capita, transportation added value, energy structure, energy intensity, and transportation intensity, on carbon emissions. Based on these factors, a scenario analysis, combined with a forecasting model, is used to predict the peak carbon performance of the transportation industry under different development scenarios. The results show that the overall carbon emissions of transportation in the YEB from 2006 to 2020 show a fluctuating upward trend, and the downstream carbon emissions are significantly higher than those in other regions. The main factors influencing carbon emissions from transportation in different upstream, midstream, and downstream regions vary, with both population and economic factors contributing to carbon emissions, while technical factors affect them differently. There are significant differences in the peak carbon performance of transportation under different development scenarios, and the government should take effective measures to work towards achieving the goals of the low-carbon or enhanced low-carbon scenarios. [ABSTRACT FROM AUTHOR]

Electrochemical CO2 reduction is a promising method for converting atmospheric CO2 into valuable low‐carbon chemicals. In this study, a crystalline cadmium sulfide/amorphous cadmium hydroxide composite was successfully deposited on the carbon paper substrate surface by in‐situ chemical bath deposition (named as c‐CdS/a‐Cd(OH)2/CP electrodes) for the efficient electrochemical CO2 reduction to produce CO. The c‐CdS/a‐Cd(OH)2/CP electrode exhibited high CO Faradaic efficiencies (>90 %) under a wide potential window of 1.0 V, with the highest value reaching ~100 % at the applied potential ranging from −2.16 V to −2.46 V vs. ferrocene/ferrocenium (Fc/Fc+), superior to the crystalline counterpart c‐CdS/CP and c‐CdS/c‐Cd(OH)2@CP electrodes. Meanwhile, the CO partial current density reached up to 154.7 mA cm−2 at −2.76 V vs. Fc/Fc+ on the c‐CdS/a‐Cd(OH)2/CP electrode. The excellent performance of this electrode was mainly ascribed to its special three‐dimensional structure and the introduction of a‐Cd(OH)2. These structures could provide more active sites, accelerate the charge transfer, and enhance adsorption of *COOH intermediates, thereby improving the CO selectivity. Moreover, the electrolytes consisting of 1‐butyl‐3‐methylimidazolium tetrafluoroborate and acetonitrile also enhanced the reaction kinetics of electrochemical CO2 reduction to CO. [ABSTRACT FROM AUTHOR]

This paper presents a numerical method for the optimal tailoring of volume fraction distributions of reinforcement materials (pillars) within FGM (functionally graded material) sandwich beams with FG-CNTRC (functionally graded CNT-reinforced composite) facesheets. Since the mechanical behaviors of sandwich beams vary depending on the distribution pattern of reinforcement materials (CNT and ceramic in this paper) through the thickness, the tailoring of these distribution patterns is important to enhance the mechanical performance. In the present study, the thickness-wise distributions of CNT in the facesheets and ceramic in the core are optimized to maximize the fundamental natural frequency of sandwich beams, based on the exterior penalty-function method and the golden section method. The developed optimization method is verified and the resulting optimum distributions of CNT and ceramic are compared with the primitive functionally graded distribution patterns which are widely adopted in the literature. Moreover, the volume fraction distributions of CNT and ceramic are also individually optimized, and the optimum results between simultaneous (SO) and individual optimizations (IO) are compared. [ABSTRACT FROM AUTHOR]

In the realm of electrochemical nitrite detection, the potent oxidizing nature of nitrite typically necessitates operation at high detection potentials. However, this study introduces a novel approach to address this challenge by developing a highly sensitive electrochemical sensor with a low reduction detection potential. Specifically, a copper metal nanosheet/carbon paper sensitive electrode (Cu/CP) was fabricated using a one-step electrodeposition method, leveraging the catalytic reduction properties of copper's high occupancy d-orbital. The Cu/CP sensor exhibited remarkable performance in nitrite detection, featuring a low detection potential of −0.05 V vs. Hg/HgO, a wide linear range of 10~1000 μM, an impressive detection limit of 0.079 μM (S/N = 3), and a high sensitivity of 2140 μA mM−1cm−2. These findings underscore the efficacy of electrochemical nitrite detection through catalytic reduction as a means to reduce the operational voltage of the sensor. By showcasing the successful implementation of this strategy, this work sets a valuable precedent for the advancement of electrochemical low-potential nitrite detection methodologies. [ABSTRACT FROM AUTHOR]

A highly sensitive sensor based on carbon fiber paper modified with a shungite–copper formazanate composite is presented for the voltammetric determination of lidocaine. The synthesized organometallic complex, composite, and modified electrode are characterized by infrared spectroscopy, high-resolution mass spectrometry, elemental analysis, scanning electron microscopy, and cyclic and linear sweep voltammetry. The twofold increase in the current of the lidocaine oxidation peak on the modified electrode compared to the unmodified one is associated with the sensitizing effect of the composite modifier, which is due to an increase in the electroactive area and the number of lidocaine binding sites on the electrode surface. The sensor exhibits a wide dynamic range from 2 to 2120 µM with a low limit of detection of 0.18 µM lidocaine and high sensitivity of 0.755 µA/V µM. The interelectrode and intraelectrode repeatability of the analytical signal do not exceed 3.5%. The sensor response is stable within three weeks. The developed sensor was used for the determination of lidocaine in pharmaceuticals. The results of an analysis of real samples demonstrated good reproducibility (RSD ≤ 5.5%) and recovery (98–102%). [ABSTRACT FROM AUTHOR]

China's carbon market is an important way to achieve carbon peak by 2030 and carbon neutrality by 2060. Blockchain technology can solve the problems of low trading efficiency, poor liquidity and regional heterogeneity in China's current carbon market. this paper explores the scenario of applying blockchain technology to China's carbon market. Firstly, this paper considers the allocation of carbon quota in the carbon market based on blockchain technology under policy regulation. The study found that the development of carbon trading pilots was uneven, and some pilot carbon trading volumes were low, presenting a situation of "no market price". Secondly, it describes the enhancement effect of blockchain technology on the carbon market from the perspective of technology and multiple factors. Considering only the technical factors, the enhancement process is an "inverted L" shape, while considering the superposition factors, the enhancement effect is approximately an "S" shape. Finally, based on the social learning model of major technological changes, the paper describes the process of dynamic utilization of blockchain technology by carbon trading enterprises and simulates the evolution law. The government should introduce relevant policies to guide the implementation of blockchain technology in the carbon market to strengthen the vitality of the carbon market and meet the expectation of carbon emission reduction. This paper provides theoretical support for the integration of blockchain technology into China's carbon market. [ABSTRACT FROM AUTHOR]

Using a panel data set from 2007 to 2019, we empirically evaluate the impact of carbon capture, utilization, and storage (CCUS) technology innovation on green total factor productivity (GTFP). The findings show that (1) CCUS technology innovation significantly improves GTFP. (2) CCUS technology innovation significantly contributes to GTFP by promoting industrial structure upgrading and carbon emissions efficiency. (3) Environmental regulation plays a positive moderating role in the nexus between CCUS technology innovation and GTFP. The findings of this paper provide guidance for China to achieve green energy transition and build a green energy system. [ABSTRACT FROM AUTHOR]

This article explores the impact of Carbon Capture, Utilization, and Storage (CCUS) technology innovation on green total factor productivity (GTFP) in China. The study finds that CCUS technology innovation has a positive effect on GTFP by improving industrial structure and carbon emissions efficiency. Environmental regulations also contribute to this relationship. The author suggests further research to refine the measurement of GTFP and address potential issues in the analysis. They also recommend conducting a heterogeneity analysis and mediation test to understand the mechanism of CCUS technology innovation on GTFP. Overall, this study provides valuable insights into the relationship between CCUS adoption and environmental productivity in China. [Extracted from the article]

This study investigates the impact of plasma gradient modification and gradient illumination on the optoelectronic properties of buckypaper (BP), a flexible and large-scale material composed of multi-walled carbon nanotubes (MWCNTs). The BP samples were subjected to argon ion plasma treatment at varying power levels and durations, thereby creating different carrier concentration gradients on the surface. The photovoltage and photocurrent responses of the samples were then measured under uniform full illumination and gradient illumination conditions. The findings revealed that both plasma gradient modification and gradient illumination significantly enhanced the optoelectronic performance of BP. Notably, the combined application of these two methods yielded superior results compared to the application of either method alone. Specifically, the optimal plasma power for improving BP was found to be 20 W. Under conditions of plasma gradient modification and gradient illumination, a photovoltage of 267.76 μV was generated, which represents a 21.44 times increase, and a photocurrent of 15.69 μA, reflecting a 32.69 times enhancement. The mechanism underlying this optoelectronic effect can be attributed to the presence of π-bonds in the carbon atoms. These π-bonds are excited by photons, resulting in the generation of small voltages and currents. This study underscores the potential of BP as an optoelectronic material and introduces a novel approach to enhance its optoelectronic properties through plasma gradient modification and gradient illumination. [ABSTRACT FROM AUTHOR]

Background: Efficient monitoring of glucose concentration in the human body necessitates the utilization of electrochemically active sensing materials in nonenzymatic glucose sensors. However, prevailing limitations such as intricate fabrication processes, lower sensitivity, and instability impede their practical application. Herein, ternary Cu-Co-Ni-S sulfides nanoporous network structure was synthesized on carbon fiber paper (CP) by an ultrafast, facile, and controllable technique through on-step cyclic voltammetry, serving as a superior self-supporting catalytic electrode for the high-performance glucose sensor. Results: The direct growth of free-standing Cu-Co-Ni-S on the interconnected three-dimensional (3D) network of CP boosted the active site of the composites, improved ion diffusion kinetics, and significantly promoted the electron transfer rate. The multiple oxidation states and synergistic effects among Co, Ni, Cu, and S further promoted glucose electrooxidation. The well-architected Cu-Co-Ni-S/CP presented exceptional electrocatalytic properties for glucose with satisfied linearity of a broad range from 0.3 to 16,000 μM and high sensitivity of 6829 μA mM− 1 cm− 2. Furthermore, the novel sensor demonstrated excellent selectivity and storage stability, which could successfully evaluate the glucose levels in human serum. Notably, the novel Cu-Co-Ni-S/CP showed favorable biocompatibility, proving its potential for in vivo glucose monitoring. Conclusion: The proposed 3D hierarchical morphology self-supported electrode sensor, which demonstrates appealing analysis behavior for glucose electrooxidation, holds great promise for the next generation of high-performance glucose sensors. [ABSTRACT FROM AUTHOR]

Carbon fiber paper (CFP) is one of the most widely used gas diffusion layer materials for proton exchange membrane fuel cells (PEMFC) due to its excellent properties such as high conductivity, high strength, high air permeability and corrosion resistance. In this study, CFP was prepared using the phenolic resin (PF) in-pulp addition method. The effect of PF content on the properties of hot-pressed paper (HPP) and CFP was investigated. The results showed that when the dosage of polyethylene oxide (PEO) was 1.5 wt%, the flocculation effect of PEO on PF was basically complete, and the water filterability and retention of carbon fiber pulp were relatively optimal. After HPP was carbonized into CFP, the hydrophobicity, average pore size, porosity, and air permeability increased, while the resistivity and tensile strength decreased. With the increase of PF content, the tensile strength of CFP gradually increased, while the average pore size, porosity, air permeability and resistivity decreased. When the PF content was 250 wt%, the average pore size of CFP was 36.5 μm, the water contact angle was 127°, the porosity was 69.7%, the air permeability was 7.81 × 103 mL mm/(cm2·h·mmHg), the resistivity was 21.1 mΩ cm, and the tensile strength was 15.7 MPa. In addition, the CFP prepared using PF in-pulp addition method had a relativity uniform pore size distribution and high air permeability. Therefore, this work shows that the CFP prepared using this technique exhibits excellent comprehensive performance, and enables the manufacturing of CFP to be more efficient, low-cost, and environmentally friendly. [Display omitted] • Carbon fiber paper was prepared efficiently using the phenolic resin in-pulp addition method. • Polyethylene oxide exhibits strong adsorption ability on phenolic resin in carbon fiber pulp. • The melting temperature of phenolic resin is a critical point in the preparation process of carbon fiber paper. • Carbon fiber paper possesses a relatively uniform pore size distribution and high air permeability. [ABSTRACT FROM AUTHOR]

One of the biggest challenges to the sustainable manufacture of liquid ammonia and the prevention of worldwide water contamination is the development of effective electrocatalysts for the electrochemical reduction of nitrate (NO 3 −) to NH 3 with high stability. Herein, a highly active and serviceable electrocatalyst is synthesized by pyrolysis, composed of nanostructure nickel phosphide (Ni 2 P) embedded in nitrogen phosphide doped carbon (NPC) followed by deposition on carbon paper (CP) to improve the electrocatalytic nitrate reduction. Various characterization techniques investigate the crystallinity, morphology, and chemical components of the Ni 2 P-NPC/CP nanoparticles. The results support the formation of nanostructure Ni 2 P and strong synergistic interactions between Ni 2 P and NPC, which resulted in substantial active sites and high electrical conductivity. Excellent performance of Ni 2 P-NPC/CP nanoparticles is achieved for electrocatalytic NO 3 − reduction with an NH 4 + yield rate of 2.468 mg h−1 mg cat. −1 and Faradaic efficiency (FE) of 84.6% at −1.2 V vs. RHE. Additionally, Ni 2 P-NPC/CP nanoparticles exhibit exceptional robustness and endurance. Studies using isotope labeling have been carried out, and the results show that nitrate reduction produces ammonia. Ni 2 P-based electrocatalysts can effectively treat nitrate wastewater to recover ammonia and facilitate its use in diverse industrial applications. • Ni 2 P-NPC/CP offers a highly active and durable electrocatalyst for the conversion of nitrate to ammonia. • Ni 2 P-NPC/CP achieved NH 4 + yield rate of 2.468 mmol h−1 mgcat−1 and Faradaic efficiency of 84.6% at −1.2 V. • The unique Ni 2 P-NPC/CP ensures robustness and practical options for continuous nitrate reduction processes. • Ni 2 P-NPC/CP offers a carbon-free energy solution through the selective conversion of nitrate to NH 3. [ABSTRACT FROM AUTHOR]

Flexible paper-based materials play a crucial role in the field of flexible electromagnetic shielding due to their thinness and controllable shape. In this study, we employed the wet paper forming technique to prepare carbon fiber paper with a thickness gradient. The electromagnetic shielding performance of the carbon fiber paper varies with the ladder-like thickness distribution. Specifically, an increase in thickness gradient leads to higher reflectance of the carbon fiber paper. Within the X-band frequency range (8.2–12.4 GHz), reflectivity decreases as electromagnetic wave frequency increases, indicating enhanced penetration of electromagnetic waves into the interior of the carbon fiber paper. This enhancement is attributed to an increased fiber content per unit area resulting from a greater thickness gradient, which further enhances reflection loss and promotes internal multiple reflections and scattering effects, leading to increased absorption loss. Notably, at a 5 mm thickness, our carbon fiber paper exhibits an impressive average overall shielding performance, reaching 63.46 dB. Moreover, it exhibits notable air permeability and mechanical properties, thereby assuming a pivotal role in the realm of flexible wearable devices in the foreseeable future. [ABSTRACT FROM AUTHOR]

Global energy security is a growing worldwide concern in the presence of high economic policy uncertainty (EPU) that can be addressed by advancing sustainable energy diversification (ED) practices. Energy security can be estimated by combining ED and EPU indices; hence, this study uses a dataset covering three continents and 26 countries from 1995 to 2023 to measure energy security employing this approach. The study employs quantile regression and panel data analysis, finding a positive relationship between EPU and ED. The results reveal that when EPU increases, the spectrum of energy sources declines, negatively impacting energy security. Other factors of globalization, Gross Domestic Product, gross capital formation, and the labor force also have an impact on the spectrum of energy sources. To obtain a sustainable level of ED, policymakers should increase investment in gross capital formation because economic growth and openness via pro-global policies have less impact on ED. This study also demonstrates that labor capital shifts have a significant effect on ED. The quantitative results reveal the importance of clear and precise economic policies for increasing investment in carbon-free energy security. [Display omitted] [ABSTRACT FROM AUTHOR]

In a proton exchange membrane fuel cell (FC), the gas diffusion layer (GDL) is identified as the component that is most affected by mechanical compression. In this article, a particular focus is provided on the methods to measure the three main electrical parameters—contact resistance, through‐plane resistance, and in‐plane resistance—of the GDL under compression. A nonlinear decrease of these resistances under compression is typically observed. In particular, an important decrease is observed from 0 to 2 MPa, then a lower one above 2 MPa. The smallest contact and in‐plane resistances are measured for the graphitized straight carbon papers analyzing GDL resistances under compression gives a first approach to explaining ohmic losses in FCs as a large part of these losses is related to the GDL. This review would be helpful for researchers in better understanding ohmic losses and establishing a database of main GDL electrical resistances and their variations according to several operating parameters. These data could be used in design models to optimize GDL properties. [ABSTRACT FROM AUTHOR]

Environmental pollution is a significant problem and is increasing gradually as more and more harmful pollutants are being released into water bodies and the environment. Water pollutants are dangerous and pose a threat to all living organisms and the ecosystem. Paper waste is one of the most widespread and largest wastes in the world. This research aims to address two important problems simultaneously: the reduction in solid waste in the environment using activated carbon from paper waste as potential adsorbents and the removal of harmful contaminants from water. Carbon from paper waste was activated with H2O2, HNO3, and KMnO4 for the adsorption of Cr(VI) and MB. SEM, EDX, FTIR, Raman, and BET were used to determine the properties of the materials. The surface morphology of the materials consisted of amorphous particles. EDX shows that all activated samples have a higher content of (O) than carbon paper waste. Adsorption studies showed that there was a stronger interaction between the pollutants and the adsorbent at a higher initial concentration (200 mg/L) than at the lower initial concentrations. The contact time data show that uptake increases when the interaction time between the contaminant and the adsorbent is increased. The tests for the pH of the solution show that the adsorption of Cr(VI) decreases when the pH is gradually increased, whereas the adsorption of MB increases when the pH of the solution is increased. The results fit better with the Freundlich isotherm and PSO models. The temperature studies show that the enthalpy was positive, indicating that the uptake process is endothermic. The Gibbs free energy values were all negative, indicating that adsorption between the adsorbents and the pollutants was favored. After four consecutive cycles, all the samples retained more than 60% of their uptake capability. [ABSTRACT FROM AUTHOR]

Residential owned solar panels mounted on roof-tops generated 1.4% of the U.S. electricity supply in 2022. Utilities compensate residential customers using a net metering system by which each kilowatt-hour generated by the customer reduces the customer's bill by the amount the utility charges for one kilowatt. Despite the small impact of roof-top solar on the total market, in 2022, thirty-two states conducted ninety-four proceedings investigating whether to change the net metering system. In these proceedings, utilities advocated changing the rates to discourage residential investment in solar panels. Utilities argue that net metering provides a subsidy to solar customers because the rate the utility pays is greater than the avoided cost of energy. That excess payment allows solar customers to avoid paying for the distribution network. The cost of the distribution network is shifted to non-solar customers. This article will evaluate these claims. It will show that if the social cost of carbon were in the calculation, it would generate a Kapp cost shift from solar customers to non-solar customers. The size of the Kapp cost shift is greater than the cost of distribution networks, reversing any private cost shift that utilities have estimated. [ABSTRACT FROM AUTHOR]

Sluggish transfer kinetics caused by solid–solid contact at the lithium (Li)/solid-state electrolyte (SE) interface is an inherent drawback of all-solid-state Li metal batteries (ASSLMBs) that not only limits the cell power density but also induces uneven Li deposition as well as high levels of interfacial stress that deteriorates the internal structure and cycling stability of ASSLMBs. Herein, a fast Li+ transfer scaffold is proposed to overcome the sluggish kinetics at the Li/SE interface in ASSLMBs using an α-MnO2-decorated carbon paper (CP) structure (α-MnO2@CP). At an atomic scale, the tunnel structure of α-MnO2 exhibits a great ability to facilitate Li+ adsorption and transportation across the inter-structure of α-MnO2@CP, leading to a high critical current density of 3.95 mA cm−2 at the Li/SE interface. Meanwhile, uniform Li deposition can be guided along the skeletons of α-MnO2@CP with minimized volume expansion, significantly improving the structural stability of the Li/SE interface. Based on these advantages, the ASSLMBs using α-MnO2@CP protected the Li anode and can stably cycle up to very high charge/discharge rates of 10C/10C, paving the way for developing high-power ASSLMBs. [ABSTRACT FROM AUTHOR]

Potassium–oxygen batteries (KOBs) are a promising energy storage technology with high theoretical energy density, low overpotential and a long cycle life. The cathode microstructure plays a significant role in the electrochemical performance of KOB. In this article, hierarchical porosity was introduced to commercially available carbon paper cathodes by thermal pretreatment in air at different pretreatment times. This pretreatment modifies the properties, such as surface area, defects, oxygen functional groups, etc. The discharge performance was determined at three different current densities, i.e., 0.1 mA/cm2, 0.5 mA/cm2, and 1.0 mA/cm2. It has been found that an increase in specific surface area with the introduction of micropores and mesopores is beneficial for the improvement in the discharge capacity by enabling homogeneous discharge product, KO2 distribution and high degrees of pore filling over the volume of the cathode. A reduction in the discharge overpotentials was observed, which is attributed to the introduction of oxygenic functional groups and defects. Samples treated for the longest pretreatment time of 24 h showed the highest discharge capacity of 5 mAh/cm2 and lowest discharge overpotential of 0.03 V. [ABSTRACT FROM AUTHOR]

It is significant to develop low-cost and highly efficient electrocatalysts for the hydrogen evolution reaction (HER) via electrochemical water splitting. Herein, we constructed P-doped NiCo2S4 nanowire arrays on carbon fiber paper (NiCo2S4−xPx/CFP) as a HER electrocatalyst in both acidic and alkaline media. Benefitting from P doping into NiCo2S4, the as-prepared NiCo2S4−xPx/CFP exhibits low HER overpotentials of 80 and 132 mV in acidic and alkaline media at a cathodic current density of 10 mA cm−2, respectively, which are far superior to counterparts of NiCo2S4 nanowire arrays on the carbon fiber paper (NiCo2S4/CFP). Meanwhile, the NiCo2S4−xPx/CFP presents excellent HER stability of 20 hours in acidic and alkaline media. From the results of density functional theory calculations, P doping can not only optimize the hydrogen adsorption energetics on each kind of atomic site of catalysts, but also strengthen the H2O molecule binding ability on the catalyst surface for the alkaline HER and favor kinetics of hydrogen adsorption and H2 formation on the catalyst surface for the acidic HER, eventually improving overall HER performances. The investigation of the HER mechanism modulated by P doping in our work offers novel inspiration to develop highly efficient ternary metal sulfides for the HER. [ABSTRACT FROM AUTHOR]

Buckypaper (BP), a flexible and porous material, exhibits photovoltaic properties when exposed to light. In this study, we employed radio frequency (RF) sputtering of zinc oxide (ZnO) followed by rapid thermal annealing to enhance the photovoltaic response of BP. We investigated the impact of various sputtering parameters, such as the gas flow ratio of argon to oxygen and deposition time, on the morphology, composition, resistivity, and photovoltaic characteristics of ZnO-modified BP. Additionally, the photovoltaic performance of the samples under different illumination modes and wavelengths was compared. It was found that optimal sputtering conditions—argon to oxygen flow ratio of 1:2, deposition time of 20 min, and power of 100 watts—resulted in a ZnO film thickness of approximately 45 nanometers. After annealing at 400 °C for 10 min, the ZnO-modified BP demonstrated a significant increase in photocurrent and photovoltage, along with a reduction in resistivity, compared to unmodified BP. Moreover, under gradient illumination, the ZnO-modified BP exhibited a photovoltage enhancement of 14.70-fold and a photocurrent increase of 13.86-fold, compared to uniform illumination. Under blue light, it showed a higher photovoltaic response than under other colors. The enhancement in photovoltaic response is attributed to the formation of a Schottky junction between ZnO and BP, an increased carrier concentration gradient, and an expanded light absorption spectrum. Our results validate that ZnO sputtering followed by annealing is an effective method for modifying BP for photovoltaic applications such as solar cells and photodetectors. [ABSTRACT FROM AUTHOR]

Carbon emission issues are becoming increasingly severe, and the carbon emissions in shrinking cities, primarily characterized by population loss, are often overlooked and insufficiently studied. This paper focuses on the carbon emissions from county-level administrative units in China's three northeastern provinces from 2001 to 2017. The study scientifically identified shrinking cities and measured the differences in carbon emission characteristics between growing and shrinking cities using the Theil index. Ultimately, the paper constructs a panel spatial econometric model to analyze the factors influencing them and explore their spatial effects. (1) The total carbon emissions in the Three Northeastern Provinces exhibited an inverted U-shaped trend, increasing from 734.21 million tons in 2001 to 1731.73 million tons in 2017, with the Mann–Kendall trend test showing a significant increase; spatially, this manifests as a significant positive spatial autocorrelation. (2) The region has 138 shrinking cities, accounting for over 50%; regarding carbon emission characteristics, the Theil index has consistently remained above 0.18, indicating significant differences between the carbon emissions of growing and shrinking cities. (3) The panel spatial econometric model results show that the influencing factors of carbon emissions in shrinking cities have unique directions, intensities, and spatial effects. In shrinking cities, aside from localized GDP effects and per-capita GDP acting as a suppressant, the population size has a pronounced inhibitory effect on local and surrounding carbon emissions. The analysis reveals significant differences in the carbon emission patterns and mechanisms between growing and shrinking cities; based on these results, the paper proposes differentiated carbon control strategies. [ABSTRACT FROM AUTHOR]

Sodium‐carbon dioxide (Na‐CO2) batteries are regarded as promising energy storage technologies because of their impressive theoretical energy density and CO2 reutilization, but their practical applications are restricted by uncontrollable sodium dendrite growth and poor electrochemical kinetics of CO2 cathode. Constructing suitable multifunctional electrodes for dendrite‐free anodes and kinetics‐enhanced CO2 cathodes is considered one of the most important ways to advance the practical application of Na‐CO2 batteries. Herein, RuO2 nanoparticles encapsulated in carbon paper (RuCP) are rationally designed and employed as both Na anode host and CO2 cathode in Na‐CO2 batteries. The outstanding sodiophilicity and high catalytic activity of RuCP electrodes can simultaneously contribute to homogenous Na+ distribution and dendrite‐free sodium structure at the anode, as well as strengthen discharge and charge kinetics at the cathode. The morphological evolution confirmed the uniform deposition of Na on RuCP anode with dense and flat interfaces, delivering enhanced Coulombic efficiency of 99.5% and cycling stability near 1500 cycles. Meanwhile, Na‐CO2 batteries with RuCP cathode demonstrated excellent cycling stability (>350 cycles). Significantly, implementation of a dendrite‐free RuCP@Na anode and catalytic‐site‐rich RuCP cathode allowed for the construction of a symmetric Na‐CO2 battery with long‐duration cyclability, offering inspiration for extensive practical uses of Na‐CO2 batteries. [ABSTRACT FROM AUTHOR]

Copyright of China Pulp & Paper is the property of China Pulp & Paper Magazines Publisher and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Hydrogen fuel is a non-toxic and source-abundant energetic system, but for its applications in the industry, several issues related to its storage must be resolved. Compounds like NaBH 4 appear as promising hydrogen sources, while can release the latter rapidly under controllable conditions with the use of heterogeneous catalyst systems. In this work, we synthesized a Ni–CoP catalyst by electrodeposition in a three-step process on carbon paper as support. The materials were characterized via SEM-EDS, XRD, and XPS techniques, while the hydrogen evolution reaction (HER) from alkaline NaBH 4 solutions was tested as a batch experiment. Ni–CoP catalyst showed a high amount of H 2 generated in a short time (∼550 mL in 1 min) and remained at 78 and 54% of its initial performance after respectively 100 and 300 h of a continuous hydrolysis process. Our catalyst revealed exceptional performance and stability at higher temperatures and a long process time, which have been a rare subject of investigation in other reports for NaBH 4 hydrolysis in the past. This work paves a new perspective in studying catalysts for hydrogen generation from borohydrides. [Display omitted] • Ni–CoP catalyst was electrodeposited on a carbon support. • Material characterization proved the formation of desired active layers. • High efficiency and stability of the catalyst for a long-term NaBH 4 hydrolysis was revealed. [ABSTRACT FROM AUTHOR]