Copper-based bimetallic catalysts have been recently showing promising performance for the selective electrochemical reduction of CO2. In this work, we successfully fabricated the partially reduced oxides SnOx, CuOxmodified Cu foam electrode (A-Cu/SnO2) through an electrodeposition-annealing-electroreduction approach. Notably, in comparison with the control electrode (Cu/SnO2) without undergoing annealing step, A-Cu/SnO2 exhibits a significant enhancement in terms of CO2 reduction activity and CO selectivity. By investigating the effect of the amount of the electrodeposited SnO2, it is found that A-Cu/SnO2 electrodes present the characteristic Sn-Cu synergistic catalysis with a feature of dominant CO formation (CO faradaic efficiency, 70~75%), the least HCOOH formation (HCOOH faradaic efficiency, <5%) and the remarkable inhibition of hydrogen evolution reaction. In contrast, Cu/SnO2 electrodes exhibit a SnO2 coverage-dependent catalysis—a shift from CO selectivity to HCOOH selectivity with the increasing deposited SnO2 on Cu foam. The different catalytic performance between Cu/SnO2 and A-Cu/SnO2 might be attributed to the different content of Cu atoms in SnO2 layer, which may affect the density of Cu-Sn interface on the surface. Our work provides a facile annealing-electroreduction strategy to modify the surface composition for understanding the metal effect towards CO2 reduction activity and selectivity for bimetallic Cu-based electrocatalysts.
Surface Strain Effect Engineers the Catalytic Performance of Pd Nanocrystals in CO2 Electrochemical Reduction
