Graphenylene-supported single-atom (Ru and Mo) catalysts for CO and NO oxidations

Abstract

Based on density functional theory (DFT) calculations, the adsorption geometries, stability and catalytic properties of single-atom Ru and Mo anchored on graphenylene sheets (gra-Ru and gra-Mo) are comparatively investigated. Compared with isolated gas molecules, different kinds of coadsorbed gas reactants (2NO, 2CO, CO–O₂ and NO–O₂) exhibit high stability on gra-Ru and gra-Mo sheets, and the coadsorbed configurations of gas reactants are considered as initial states for the NO and CO oxidation reactions. According to the calculated energy barriers, NO oxidation reactions on the gra-Ru sheet through the Langmuir–Hinshelwood (LH) mechanism have relatively large energy barriers than CO oxidation reactions. In addition, the preadsorbed 2NO reacting with 2CO (2NO + 2CO → 2CO₂ + N₂) on gra-Ru and gra-Mo sheets through the Eley–Rideal (ER) mechanism (<0.5 eV) are energetically more favorable reactions. Therefore, different kinds and adsorption geometries of gas reactants have a close relationship with the reaction mechanism and energy barriers for the NO and CO oxidation, which provide an important reference for designing novel graphenylene-based catalysts for the removal of toxic gases.