Strategic regulation of nitrogen-containing intermediates for enhanced nitrate reduction over Co_(3)O_(4)/SiC catalyst having multiple active centers  

作　　者：Ming-Hao Guan Hao-Nan Xu Jin Liu Tao Wu An-Hui Lu 

机构地区：[1]State Key Laboratory of Fine Chemicals,Liaoning Key Laboratory for Catalytic Conversion of Carbon Resources,School of Chemical Engineering,Dalian University of Technology,Dalian 116024,Liaoning,China

出　　处：《Journal of Energy Chemistry》2024年第9期291-299,共9页能源化学（英文版）

基　　金：financially supported by the National Key Research and Development Program of China (2018YFA0209404);the Fundamental Research Funds for the Central Universities (DUT22LAB601)

摘　　要：Regulating the intermediates involved in the electrocatalytic nitrate reduction reaction(NO_(3)RR)is crucial for the enhancement of reaction efficiency.However,it remains a great challenge to regulate the reaction intermediates through active site manipulation on the surface of the catalyst.Here,a family of n%-Co_(3)O_(4)/SiC(n=5,8,12,20)catalysts with a delicate percentage of Co^(2+)and Co^(3+)were prepared for NO_(3)RR.We found that Co^(3+)primarily acts as the active site for NO_(3)^(−)reduction to NO_(2)^(−),while Co^(2+)is responsible for the conversion of NO_(2)^(−)to NH_(3).Moreover,the conversion of these intermediates over the active sites is autonomous and separately controllable.Both processes synergistically accomplish the reduction of nitrate ions to synthesize ammonia.Combining the experimental studies and density functional theory(DFT)calculations,it is discovered the pathway(^(*)NHO→^(*)NHOH→^(*)NH_(2)OH→^(*)NH_(2)→^(*)NH_(3))is more favorable due to the lowerΔG value(0.25 eV)for the rate-limiting step(^(*)NO→^(*)NHO).The NH_(3)yield rate of 8%-Co_(3)O_(4)/SiC reached 1.08 mmol/(cm^(2)h)with a Faradaic efficiency of 96.4%at−0.89 V versus the reversible hydrogen electrode(RHE),surpassing those of most reported non-noble NO_(3)RR catalysts.This strategy not only provides an efficient catalyst for NO_(3)RR but also serves as an illustrative model for the regulation of multi-step reaction intermediates through the design of distinct active sites,thereby presenting a new approach to enhance the efficiency of intricate reactions.

关 键 词：ELECTROCATALYSIS Nitratereduction Co_(3)O_(4)/SiC catalysts Intermediates control 

分 类 号：TQ113.2[化学工程—无机化工] O643.36[理学—物理化学]