Mechanism of NO electrocatalytic reduction over the MoS2-based single atom catalyst: A DFT investigation

Abstract

The emission of Nitric Oxide (NO) is a critical issue in the area of global environmental pollution. The electrocatalytic reduction of Nitric Oxide (NORR) for controlling NO pollution and generating ammonia has attracted significant attention in recent years, wherein the transition metal single atom catalyst (SAC) exhibits especially decent performance. However, the interaction mechanism between reactants and the NORR catalyst remains unclear at the current stage. Herein, this study explored the NORR mechanism on the MoS₂-based transition metal SACs. Density functional theory calculations were employed to determine the superior SAC catalyst for NORR by evaluating the electrochemical stability, adsorption performance, and NORR reactivity. Results showed that Mn-MoS₂ exhibited excellent performance in terms of electrochemical stability and NO adsorption. Based on electronic structure analysis, Mn altered the electronic state distribution of MoS₂, enhancing charge transfer intensity. Hybridization of different orbitals indicated the stronger interaction between Mn and NO, promoting the adsorption of NO on the surface of MoS₂. Calculation of Gibbs free energy of NORR steps confirmed that Mn-MoS₂ reduced the energy barrier of the rate determining step in NORR and accelerated the reaction process. This study provides a theoretical foundation for the development of advanced SACs, emphasizing the promising role of Mn in enhancing catalytic efficiency.