Nb2S2C Monolayers with Transition Metal Atoms Embedded at the S Vacancy Are Promising Single-Atom Catalysts for CO Oxidation.

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 Nb2S2C 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 Nb2S2C. After estimating the structure stability, the aggregation trend of the embedded metal atoms, and adsorption strength of reactants and products, Zn-decorated defective Nb2S2C 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.