Compressive strain in Cu catalysts:Enhancing generation of C2+products in electrochemical CO_(2)reduction

铜催化剂中的压缩应变增强电催化CO_(2)还原多碳产物生成

Elastic strain in Cu catalysts enhances their selectivity for the electrochemical CO_(2)reduction reaction(eCO_(2)RR),particularly toward the formation of multicarbon(C_(2+))products.However,the reasons for this selectivity and the effect of catalyst precursors have not yet been clarified.Hence,we employed a redox strategy to induce strain on the surface of Cu nanocrystals.Oxidative transformation was employed to convert Cu nanocrystals to CuxO nanocrystals;these were subsequently electrochemically reduced to form Cu catalysts,while maintaining their compressive strain.Using a flow cell configuration,a current density of 1 A/cm^(2)and Faradaic efficiency exceeding 80%were realized for the C_(2+)products.The selectivity ratio of C_(2+)/C1 was also remarkable at 9.9,surpassing that observed for the Cu catalyst under tensile strain by approximately 7.6 times.In-situ Raman and infrared spectroscopy revealed a decrease in the coverage of K+ion-hydrated water(K·H_(2)O)on the compressively strained Cu catalysts,consistent with molecular dynamics simulations and density functional theory calculations.Finite element method simulations confirmed that reducing the coverage of coordinated K·H_(2)O water increased the probability of intermediate reactants interacting with the surface,thereby promoting efficient C–C coupling and enhancing the yield of C_(2+)products.These findings provide valuable insights into targeted design strategies for Cu catalysts used in the eCO_(2)RR.