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Electrodeposited porous Pb electrode with improved electrocatalytic performance for the electroreduction

Jing WANG, Hua WANG, Zhenzhen HAN, Jinyu HAN

《化学科学与工程前沿（英文）》 2015年第9卷第1期页码 57-63 doi: 10.1007/s11705-014-1444-8

摘要： A porous Pb foam was fabricated electrochemically at a copper substrate and then used as the cathode for the electroreduction of CO . The surface morphology and composition of the porous Pb electrode was characterized by scanning electron microscopy, X-ray diffraction, transmission electron microscopy and selected area electron diffraction. The honeycomb-like porous structure was composed of needle-like Pb deposits. Cyclic voltammetry studies demonstrated that the porous Pb electrode had better electrocatalytic performance for the formation of formic acid from CO compared with a Pb plate electrode. The increase in current density was due to the large surface area of the porous Pb electrode, which provides more active sites on the electrode surface. The improved formic acid selectivity was due to the morphology of the roughened surface, which contains significantly more low-coordination sites which are more active for CO reduction. The highest current efficiency for formic acid was 96.8% at -1.7 V versus saturated calomel electrode at 5 °C. This porous Pb electrode with good catalytic abilities represents a new 3D porous material with applications for the electroreduction of CO .

关键词： electrodeposited porous Pb carbon dioxide electroreduction formic acid

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Electrochemical removal of nitrate in industrial wastewater

Dong Xu, Yang Li, Lifeng Yin, Yangyuan Ji, Junfeng Niu, Yanxin Yu

《环境科学与工程前沿（英文）》 2018年第12卷第1期 doi: 10.1007/s11783-018-1033-z

摘要： A number of recent studies have demonstrated that electrochemical technologies, including electroreduction (ER), electrocoagulation (EC), and electrodialysis (ED), are effective in nitrate elimination in wastewater due to their high reactivity. To obtain the maximal elimination efficiency and current efficiency, many researchers have conducted experiments to investigate the optimal conditions (i.e., potential, current density, pH value, plate distance, initial nitrate concentration, electrolyte, and other factors) for nitrate elimination. The mechanism of ER, EC and ED for nitrate removal has been fully elucidated. The ER mechanism of nitrate undergoes electron transfer and hydrogenation reduction. The EC pathways of nitrate removal include reduction, coagulation and flotation. The ED pathways of nitrate include redox reaction and dialysis. Although the electrochemical technology can remove nitrate from wastewater efficiently, many problems (such as relatively low selectivity toward nitrogen, sludge production and brine generation) still hinder electrochemical treatment implementation. This paper critically presents an overview of the current state-of-the-art of electrochemical denitrification to enhance the removal efficiency and overcome the shortages, and will significantly improve the understanding of the detailed processes and mechanisms of nitrate removal by electrochemical treatment and provide useful information to scientific research and actual practice.

关键词： Nitrate removal Electroreduction Electrocoagulation Electrodialysis

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Electrochemical CO reduction to C products over CuZn intermetallic catalysts synthesized by electrodeposition

《能源前沿（英文）》 doi: 10.1007/s11708-023-0898-0

摘要： Electrocatalytic CO₂ reduction (ECR) offers an attractive approach to realizing carbon neutrality and producing valuable chemicals and fuels using CO₂ as the feedstock. However, the lack of cost-effective electrocatalysts with better performances has seriously hindered its application. Herein, a one-step co-electrodeposition method was used to introduce Zn, a metal with weak *CO binding energy, into Cu to form Cu/Zn intermetallic catalysts (Cu/Zn IMCs). It was shown that, using an H-cell, the high Faradaic efficiency of C₂₊ hydrocarbons/alcohols (

F E C 2 +

) could be achieved in ECR by adjusting the surface metal components and the applied potential. In suitable conditions, FE_C2+ and current density could be as high as 75% and 40 mA/cm², respectively. Compared with the Cu catalyst, the Cu/Zn IMCs have a lower interfacial charge transfer resistance and a larger electrochemically active surface area (ECSA), which accelerate the reaction. Moreover, the *CO formed on Zn sites can move to Cu sites due to its weak binding with *CO, and thus enhance the C–C coupling on the Cu surface to form C₂₊ products.

关键词： carbon dioxide electroreduction electrochemistry co-electrodeposition intermetallic catalysts value-added chemicals

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Boosting the direct conversion of NHHCO electrolyte to syngas on Ag/Zn zeolitic imidazolate framework derived nitrogen-carbon skeleton

《化学科学与工程前沿（英文）》 2023年第17卷第9期页码 1196-1207 doi: 10.1007/s11705-022-2289-1

摘要： The electrochemical reduction of NH₄HCO₃ to syngas can bypass the high energy consumption of high-purity CO₂ release and compression after the ammonia-based CO₂ capture process. This technology has broad prospects in industrial applications and carbon neutrality. A zeolitic imidazolate framework-8 precursor was introduced with different Ag contents via colloid chemical synthesis. This material was carbonized at 1000 °C to obtain AgZn zeolitic imidazolate framework derived nitrogen carbon catalysts, which were used for the first time for boosting the direct conversion of NH₄HCO₃ electrolyte to syngas. The AgZn zeolitic imidazolate framework derived nitrogen carbon catalyst with a Ag/Zn ratio of 0.5:1 achieved the highest CO Faradaic efficiency of 52.0% with a current density of 1.15 mA·cm^–2 at –0.5 V, a H₂/CO ratio of 1–2 (–0.5 to –0.7 V), and a stable catalytic activity of more than 6 h. Its activity is comparable to that of the CO₂-saturated NH₄HCO₃ electrolyte. The highly discrete Ag-N_x and Zn-N_x nodes may have combined catalytic effects in the catalysts synthesized by appropriate Ag doping and sufficient carbonization. These nodes could increase active sites of catalysts, which is conducive to the transport and adsorption of reactant CO₂ and the stability of *COOH intermediate, thus can improve the selectivity and catalytic activity of CO.

关键词： Ag catalyst zeolitic imidazolate framework CO₂ electroreduction ammonium bicarbonate electrolyte syngas

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Electroreduction of hexavalent chromium using a porous titanium flow-through electrode and intelligent

《环境科学与工程前沿（英文）》 2023年第17卷第8期 doi: 10.1007/s11783-023-1697-x

摘要：

● Titanium-based flow-through electrode achieved high Cr(VI) reduction efficiency.

关键词： Flow-through electrode Hexavalent chromium Heavy metals Neural network Artificial intelligence

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Preparation of a Pb loaded gas diffusion electrode and its application to CO

Ang LI, Hua WANG, Jinyu HAN, Li LIU

《化学科学与工程前沿（英文）》 2012年第6卷第4期页码 381-388 doi: 10.1007/s11705-012-1216-2

摘要： A Pb loaded gas diffusion electrode was fabricated and used for the electroreduction of CO to formic acid. The Pb/C catalyst was prepared by isometric impregnation. The crystal structure and morphology of the Pb/C catalyst were characterized by X-ray diffraction (XRD) and transmission electron microscope (TEM). The preparation conditions of the gas diffusion electrode were optimized by adjusting the amounts of polytetrafluoroethylene (PTFE) in the gas diffusion layer and acetylene black in the catalytic layer. The electrochemical performance of the as-prepared gas diffusion electrode was studied by chronoamperometry and cyclic voltammetry. The optimized gas diffusion electrode showed good catalytic performance for the electroreduction of CO . The current efficiency of formic acid after 1 h of operation reached a maximum of 22% at -2.0 V versus saturated calomel electrode (SCE).

关键词： electroreduction carbon dioxide lead catalyst gas diffusion electrode formic acid

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nanoparticle-embedded porous carbon superstructures from a Fe-covalent triazine polymer boosting oxygen electroreduction

《化学科学与工程前沿（英文）》 2023年第17卷第5期页码 525-535 doi: 10.1007/s11705-022-2232-5

摘要： Fe–N_x nanoparticles-embedded porous carbons with a desirable superstructure have attracted immense attention as promising catalysts for electrochemical oxygen reduction reaction. Herein, we employed Fe-coordinated covalent triazine polymer for the fabrication of Fe–N_x nanoparticle-embedded porous carbon nanoflorets (Fe/N@CNFs) employing a hypersaline-confinement-conversion strategy. Presence of tailored N types within the covalent triazine polymer interwork in high proportions contributes to the generation of Fe/N coordination and subsequent Fe–N_x nanoparticles. Owing to the utilization of NaCl crystals, the resultant Fe/N@CNF-800 which was generated by pyrolysis at 800 °C showed nanoflower structure and large specific surface area, which remarkably suppressed the agglomeration of high catalytic active sites. As expect, the Fe/N@CNF-800 exhibited unexpected oxygen reduction reaction catalytic performance with an ultrahigh half-wave potential (0.89 V vs. reversible hydrogen electrode), a dominant 4e^– transfer approach and great cycle stability (> 92% after 100000 s). As a demonstration, the Fe/N-PCNF-800-assembled zinc–air battery delivered a high open circuit voltage of 1.51 V, a maximum peak power density of 164 mW·cm^–2, as well as eminent rate performance, surpassing those of commercial Pt/C. This contribution offers a valuable avenue to exploit efficient metal nanoparticles-based carbon catalysts towards energy-related electrocatalytic reactions and beyond.

关键词： Fe–N_x nanoparticles hypersaline-confinement conversion floret-like carbon covalent triazine polymers oxygen reduction reaction