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

Electrochemical CO reduction reaction (eCORR) 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 eCORR remains challenging because of the difficulty in controlling the oxidation states of Cu against robust structural reconstructions during the eCORR. Herein, we report a novel strategy for tuning the oxidation states of Cu species and achieving eCORR 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 eCORR 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 eCORR performance for CH and C products, respectively.