Design And Performance Study Of Highly Effective Non-noble Metal Electrocatalysts For Carbon Dioxide Reduction

In order to meet the needs of human development,a large number of non-renewable fossil fuels have been over-exploited and utilized,resulting in the continuous rise of atmospheric CO₂ content,which has not only caused the global energy crisis,but also caused serious environmental problems.At present,developing clean and sustainable energy technologies is an effective strategy to address energy shortages and climate change.Among them,electrocatalytic CO₂ reduction can use renewable energy to drive CO₂ to reduction into fuel and value-added chemicals,which is the most promising method.However,there are still many problems in CO₂reduction electrocatalysts,such as high catalytic cost,low catalytic energy efficiency and poor catalytic stability,etc.Therefore,it is extremely important to design and prepare inexpensive,efficient and stable non-noble metal materials for electrocatalytic CO₂ reduction materials.In order to solve the above problems,two kinds of catalysts with high energy conversion efficiency were prepared in this paper by using non-noble metal materials as the research object and designing the catalysts through structure optimization and interface regulation.The main research contents are as follows:1.Copper nanoclusters/DRC（Cu clusters/DRC）were successfully prepared by a simple impregnation-calcining route using the double constraint effect of the rich defect multi-microporous carbon materials.The diameter of the copper nanoclusters was around 1.0 nm.This catalyst has a record-high performance for the carbon dioxide reduction reaction（CO₂RR）,including high Faraday efficiency（81.7%）and partial current density(18.0 m A cm^-2)toward methane at the potential of-1 V vs reversible hydrogen electrode（RHE）,and excellent stability（40 h）.In addition,the preparation method of this material can be used as a universal method to prepare other kinds of sub-nanometal clusters and carbon composites,such as iron,cobalt,nickel,etc..2.With Co（OH）₂ 2D nanoarray as template and K₃[Co（CN）₆]as growth agent,adjacent co-PBAs nano-cubes were grown in situ.After that,the 3D material of Co S₂nanocage with S edge removed was successfully prepared by S^2-etching and heat treatment.Combined with theoretical calculation and electrochemical performance test,we discover that the design of three-dimensional network structure can expose more active sites and improve the overall catalytic performance of the material.The removal of edge S greatly inhibited the occurrence of hydrogen evolution side reaction in electrocatalytic reduction of CO₂,and significantly improved the selectivity of CO₂ reduction to CO（85.7%）.In addition,the 3D material retains excellent oxygen evolution reaction（OER）performance and can achieve"one-dose"catalytic performance,In the electrolytic cell for overall CO₂ splitting,the Hierarchical network Co S₂ nanocage material with edge S removed had a cell voltage of 1.92 V when the current density of 1 m A cm^-2 under the condition of nearly neutral electrolyte and the cathode still has high Faraday efficiency and good stability at this voltage.