Theoretical Insights\ninto Methane Activation on Transition-Metal\nSingle-Atom Catalysts Supported on the CeO₂(111) Surface

Abstract

Converting methane into high-value-added chemicals is\ncrucial for\naddressing the energy transition, where novel processes and catalysts\nare required to improve the selective activation of methane. In this\nstudy, we combined density functional theory within the Hubbard correction\ncalculations and the unity bond index-quadratic exponential potential\nmodel to investigate methane activation on TM/CeO₂(111)\nsystems, where TM represents single-adatoms of Fe, Co, Ni, Cu, Zn,\nRu, Rh, Pd, Ag, Ir, Pt, and Au. Our results indicate that the most\nstable TM adatoms on CeO₂(111) are those that donate more\nelectrons to the surface, thereby reducing the Ce cations from Ce⁴⁺ to Ce³⁺. The first methane dehydrogenation becomes\nmore thermodynamically favored as the TM period increases; that is,\nthe magnitude of both reaction and dissociation energies increases.\nIn contrast, the C–H activation energy barriers, in general,\ndecrease along with the TM period, which is related to the large magnitude\nof the CH₃ adsorption energy. Thus, our findings offer\nvaluable insights into the exploration of ceria-supported transition-metal\nsingle-atom catalysts for methane activation.