Enhancing the activity of CO2 reduction electrocatalysts via modifying metals and ligand of conductive two-dimensional metal-organic framework ligands: A theoretical study

Efficient CO2 reduction reaction (CO2RR) catalysts play a pivotal role in electrocatalytic CO2 reduction effectively addressing the imbalance in the natural carbon cycle. In this work, density functional theory (DFT) is systematically employed to investigate the reaction mechanisms of CO2RR on a series of newly prepared twodimensional MOF materials loaded with transition metal atom novel, namely TM-OxN4-x (TM = Fe, Co, Ni, Cu, and Ru; x = 0-4). The stability assessment results indicate that all catalysts exhibit good stability in terms of thermodynamics and electrochemistry. The calculated Gibbs free energies of CO2 reduction to various C1 products revealed that Ru-O1N3 and Ru-O2N2-oppo exhibit high activity toward C1 products (HCOOH, CH3OH, and CH4), with limiting potential values of-0.06 and-0.11 V, respectively. Further analysis of the electronic structure indicated that varying N/O coordination significantly alters the electronic structure of TM-OxN4-x, thereby influencing catalytic activity. Consequently, by reasonably regulating the type of metal atoms and the coordination number of N atoms, the catalytic activity and selectivity of MOF-based catalysts can be effectively improved, providing valuable theoretical insights for the rational design of effective MOF electrocatalysts.