Self-supported NiFe-LDH nanosheets on NiMo-based nanorods as high-performance bifunctional electrocatalysts for overall water splitting at industrial-level current densities

Efficient,durable and economic electrocatalysts are crucial for commercializing water electrolysis technology.Herein,we report an advanced bifunctional electrocatalyst for alkaline water splitting by growing NiFe-layered double hydroxide(NiFe-LDH)nanosheet arrays on the conductive NiMo-based nanorods deposited on Ni foam to form a three-dimensional(3D)architecture,which exhibits exceptional performances for both hydrogen evolution reaction(HER)and oxygen evolution reaction(OER).In overall water splitting,only the low operation voltages of 1.45/1.61 V are required to reach the current density of 10/500 mA·cm^(-2),and the continuous water splitting at an industrial-level current density of 500 mA·cm^(-2) shows a negligible degradation(1.8%)of the cell voltage over 1000 h.The outstanding performance is ascribed to the synergism of the HER-active NiMo-based nanorods and the OER-active NiFe-LDH nanosheet arrays of the hybridized 3D architecture.Specifically,the dense NiFe-LDH nanosheet arrays enhance the local pH on cathode by retarding OH-diffusion and enlarge the electrochemically active surface area on anode,while the conductive NiMo-based nanorods on Ni foam much decrease the charge-transfer resistances of both electrodes.This study provides an efficient strategy to explore advanced bifunctional electrocatalysts for overall water splitting by rationally hybridizing HER-and OER-active components.

CO2 electrolysis at industrial current densities using anion exchange membrane based electrolyzers

Significant progress on electrocatalytic CO2 reduction reaction (CO2RR) has been achieved in recent years.However,the research and development of electrolyzer device for CO2RR is scarce.Here we use anion exchange membrane to develop zerogap electrolyzers for CO2RR.The electrochemical properties of the electrolyzers with Pd/C and Cu cathodes are investigated.The Pd/C cathode shows a current density of 200 mA cm^-2with CO Faradaic efficiency of 98%and energy efficiency of 48.8%,while the Cu cathode shows a current density of 350 mA cm^-2with total CO2RR Faradaic efficiency of 81.9%and energy efficiency of 30.5%.This work provides a promising demonstration of CO2 electrolyzer using anion exchange membrane for CO2 electrolysis at industrial current densities.

Fully exposed nickel clusters with electron-rich centers for high-performance electrocatalytic CO_(2) reduction to CO

Single-atom catalysts(SACs)have attracted increasing concerns in electrocatalysis because of their maximal metal atom utilization,distinctive electronic properties,and catalytic performance.However,the isolated single sites are disadvantageous for reactions that require simultaneously activating different reactants/intermediates.Fully exposed metal cluster catalyst(FECC),inheriting the merits of SACs and metallic nanoparticles,can synergistically adsorb and activate reactants/intermediates on their multi-atomic sites,demonstrating great promise in electrocatalytic reactions.Here a facile method to regulate the atomic dispersion of Ni species from cluster to single-atom scale for efficient CO_(2) reduction was developed.The obtained Ni FECC exhibits high Faradaic efficiency of CO up to 99%,high CO partial current density of 347.2 mA cm^(−2),and robust durability under 20 h electrolysis.Theoretical calculations illuminate that the ensemble of multiple Ni atoms regulated by sulfur atoms accelerates the reaction kinetics and thus improves CO production.