Nb(2)S(2)C Monolayers with Transition Metal Atoms Embedded at the S Vacancy Are Promising Single-Atom Catalysts for CO Oxidation

[Image: see text] Single atoms anchored on stable and robust two-dimensional (2D) materials are attractive catalysts for carbon monoxide (CO) oxidation. Here, 3d (Fe-Zn), 4d (Ru-Cd), and 5d (Os-Hg) transition metal-decorated Nb(2)S(2)C monolayers were systematically studied as potential single-atom catalysts for low-temperature CO oxidation reactions by performing first-principles calculations. Sulfur vacancies are essential for stabilizing the transition metals anchored on the surface of defective Nb(2)S(2)C. After estimating the structure stability, the aggregation trend of the embedded metal atoms, and adsorption strength of reactants and products, Zn-decorated defective Nb(2)S(2)C is predicted to be a promising catalyst to facilitate CO oxidation through the Langmuir–Hinshelwood (LH) mechanism with an energy barrier of only 0.25 eV. Our investigation indicates that defective carbosulfides can be promising substrates to generate efficient and low-cost single-atom catalysts for low-temperature CO oxidation.