Unlocking the Potential of Zr4N4 Catalyst for CO2 Dissociation Mechanism into CO and HCOOH

Abstract

Here, we employed a Zr4N4 catalyst to investigate the electrochemical reduction of carbon dioxide (CO2) via state of art density functional theory (DFT). The active site was identified at the hollow site for the horizontal adsorption of CO2. Furthermore, the electronic properties were analyzed through HOMO–LUMO energy gap calculations, projected density of states (PDOS), and total density of states (TDOS). Based on the adsorption energies of the key intermediates (OCHO and COOH), the results reveal that CO2 reduction proceeds toward the formation of CO and HCOOH. Our study further highlights the interaction of the Zr4N4 atomic cluster as a catalyst with different hydrocarbons through Gibbs free energy analysis. The results indicate that, among the two possible pathways, the most favorable route is the formation of HCOOH. The electrochemical reduction of CO2 to formic acid and carbon monoxide was also examined in terms of the required overpotential. The calculated limiting potentials for CO and HCOOH are –0.91 V and –0.44 V, respectively. Furthermore, direct dissociation of CO2 to CO was observed using the nudged elastic band (NEB) method.