Ag single-atom modification of MgAl-LDH to enhance the CH4 product selectivity in CO2 reduction: a DFT study†

In recent years, single-atom-modified catalysts have emerged as a promising tool to enhance the efficiency and product selectivity of photocatalytic CO₂ reduction. In this work, we systematically investigated a Ag single-atom-modified MgAl-LDH catalyst using density functional theory (DFT) calculations. Our results demonstrate that the incorporation of Ag single atoms significantly reduces the energy barrier, optimizes the reaction pathway, and ultimately improves CH₄ selectivity. The calculated Gibbs free energy changes exhibit a remarkable agreement with the standard theoretical values, with a deviation of only approximately 0.1 eV, highlighting the accuracy and reliability of our computational results. Moreover, our findings further indicate that the active sites for the reactions are situated on the hydroxyl O atoms of MgAl-LDH adjacent to the Ag atoms, rather than on the Ag atoms themselves. This study offers novel insights and design principles for developing single-atom-modified materials to achieve enhanced CH₄ selectivity from a unique perspective.