Single‐Atom Catalysts Based on the Mo2CO2 MXene for CO Oxidation

Abstract Through density functional theory calculations, the mechanism of CO oxidation to CO 2 on single‐atom catalysts consisting of an atom of Ti, Fe, or Zn deposited on the surface of the Mo 2 CO 2 MXene is investigated. In the case of Fe@Mo 2 CO 2 , a mechanism resembling that of Termolecular Langmuir–Hinshelwood (TLH) is thermodynamically and kinetically favored, displaying very exothermic CO 2 formation, low activation energies, and easy CO 2 desorption. On Ti@Mo 2 CO 2 , the dissociation of CO 2 is almost barrierless and much more likely to occur than CO 2 desorption, barring the usage of this surface as a catalyst for CO oxidation. Finally, on Zn@Mo 2 CO 2 , a hybrid Langmuir–Hinshelwood/Eley–Rideal (LH/ER) mechanism is thermodynamically and kinetically feasible. Here, after the first CO 2 forms, with an energy barrier of only 0.62 eV, the second CO 2 is formed spontaneously, and the Zn–CO 2 interactions are weak enough to allow desorption. The calculated thermodynamic quantities and reaction rates at T = 300 K indicate that Fe@Mo 2 CO 2 should be quite active toward CO oxidation, followed by Zn@Mo 2 CO 2 , while the Ti‐based model is inactive. The results add to the evidence that establishes single transition metal atoms adsorbed on MXene surfaces as cheap and easily obtainable catalysts that offer the best of both bare and functionalized MXenes.