Multi-atomic loaded C2N1 catalysts for CO2 reduction to CO or formic acid

Abstract

In recent years, the development of highly active and selective electrocatalysts for the electrochemical reduction of CO₂ to produce CO and formic acid has aroused great interest, and can reduce environmental pollution and greenhouse gas emissions. Due to the high utilization of atoms, atom-dispersed catalysts are widely used in CO₂ reduction reactions (CO₂RRs). Compared with single-atom catalysts (SACs), multi-atom catalysts have more flexible active sites, unique electronic structures and synergistic interatomic interactions, which have great potential in improving the catalytic performance. In this study, we established a single-layer nitrogen–graphene-supported transition metal catalyst (TM-C₂N₁) based on density functional theory, facilitating the reduction of CO₂ to CO or HCOOH with single-atom and multi-atomic catalysts. For the first time, the TM-C₂N₁ monolayer was systematically screened for its catalytic activity with ab initio molecular dynamics, density of states, and charge density, confirming the stability of the TM-C₂N₁ catalyst structure. Furthermore, the Gibbs free energy and electronic structure analysis of 3TM-C₂N₁ revealed excellent catalytic performance for CO and HCOOH in the CO₂RR with a lower limiting potential. Importantly, this work highlights the moderate adsorption energy of the intermediate on 3TM-C₂N₁. It is particularly noteworthy that 3Mo-C₂N₁ exhibited the best catalytic performance for CO, with a limiting potential (U_L) of −0.62 V, while 3Ti-C₂N₁ showed the best performance for HCOOH, with a corresponding U_L of −0.18 V. Additionally, 3TM-C₂N₁ significantly inhibited competitive hydrogen evolution reactions. We emphasize the crucial role of the d-band center in determining products, as well as the activity and selectivity of triple-atom catalysts in the CO₂RR. This theoretical research not only advances our understanding of multi-atomic catalysts, but also offers new avenues for promoting sustainable CO₂ conversion.