Tuning CuMgAl-Layered Double Hydroxide Nanostructures to Achieve CH4 and C2+ Product Selectivity in CO2 Electroreduction

Abstract

Electrochemical CO2 reduction reaction (eCO(2)RR) over Cu-based catalysts is a promising approach for efficiently converting CO2 into value-added chemicals and alternative fuels. However, achieving controllable product selectivity from eCO(2)RR remains challenging because of the difficulty in controlling the oxidation states of Cu against robust structural reconstructions during the eCO(2)RR. Herein, we report a novel strategy for tuning the oxidation states of Cu species and achieving eCO(2)RR product selectivity by adjusting the Cu content in CuMgAl-layered double hydroxide (LDH)-based catalysts. In this strategy, the highly stable Cu2+ species in low-Cu-containing LDHs facilitated the strong adsorption of *CO intermediates and further hydrogenation into CH4. Conversely, the mixed Cu-0/Cu+ species in high-Cu-containing LDHs derived from the electroreduction during the eCO(2)RR accelerated C-C coupling reactions. This strategy to regulate Cu oxidation states using LDH nanostructures with low and high Cu molar ratios produced an excellent eCO(2)RR performance for CH4 and C2+ products, respectively.