First-principles study of an efficient non-noble metal single-atom catalyst Fe1/TiVCO2 for CO oxidation

Abstract

MXenes, a class of two-dimensional layered materials of transition metal carbides, nitrides, and carbonitrides, have piqued the interest of researchers due to their unique physical and chemical properties. The crystal structure, electronic structure, stability, and catalytic activity of a new MXene-based single-atom catalyst (SAC) Fe₁/TiVCO₂ have been studied by first principles, showing that this SAC exhibits excellent catalytic activity for CO oxidation. Research has shown that charge transfer from Fe₁/TiVCO₂ to adsorbed CO and O₂ molecules plays an important role in molecular activation. The CO oxidation mechanisms of Langmuir–Hinshelwood (LH), Eley–Rideal (ER), and termolecular Eley–Rideal (TER) were explored. All three reaction mechanisms are feasible at low temperatures, and the activation barrier energies for rate-limiting steps are 0.72 eV, 1.00 eV, and 0.40 eV, respectively. The results indicate that Fe₁/TiVCO₂ exhibits the highest activity for CO oxidation through the TER mechanism.