Engineering the interface charge redistribution and boosted kinetics via polyoxometalate for efficient carbon dioxide electroreduction in acidic medium.

The development of electrocatalytic CO2 reduction reaction (ECO2RR) which can achieve carbon neutrality goals in acidic medium can effectively solve the problems of carbonate formation and low CO2 utilization efficiency, but the inhibition of hydrogen evolution reaction (HER) is challenging. Thus, a co-modification strategy of electrolyte and electrocatalyst has been proposed to solve this issue. In a polyoxometalate (POM) H6PV3Mo9O40 modified acidic medium, the highest Faradaic efficiency (FE) and current density for carbonaceous product of POM-CuSe/rGO reach 90.8% and -176.2 mA·cm-2, respectively. Detailed research shows that the modification for catalyst by POM results in a redistribution of interfacial charges which favors the stable adsorption of *CO, as well as a reduction in the lateral size from 42 ∼ 1400 to 27 ∼ 167 nm. While the POM modification of the electrolyte leads to enhanced kinetics and suppressed CO32- production, achieving a single pass conversion efficiency for CO of up to 69.0%. This work proposes a new strategy of POM co-modification for electrolyte and electrocatalyst to enhance the efficiency of acidic CO2 conversion for industrial applications.