Tuning CuMgAl-Layered Double Hydroxide Nanostructures to Achieve CH 4 and C 2+ Product Selectivity in CO 2 Electroreduction

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