Implications of DFT calculations on microkinetic predictions: The catalytic decomposition of CH4 on M13 (M = Fe, Ni, Ru, Pd and Pt) cluster

A Kinetic Monte Carlo approach, combined with Density functional theory (DFT) calculations were employed to investigate the adsorption and dehydrogenation mechanisms of CH₄ and its intermediate species CH₃, CH₂, CH and C, on metal clusters of Fe, Ni, Ru, Pd, and Pt. Adsorption energies calculated with both PBE and dispersion-corrected PBE-D3 functionals indicates significant variations in binding strength as dehydrogenation progressed. It is notable that methane was weakly physisorbed on all metals, with adsorption energies ranging from −0.13 eV on Ru₁₃ to −0.41 eV on Pt₁₃. Activation barriers for CH₄ dehydrogenation were determined and compared with previous studies, revealing how the adsorption energies, activation energies, and reaction energies can differ based on metal type, geometry, and the chosen DFT method, and reaction pathway proposed. To complement the electronic structure and activation barrier results, a Kinetic Monte Carlo (KMC) approach was employed using the activation energies obtained from DFT to simulate the temperature-dependent evolution of surface intermediates and H₂ desorption. This multiscale strategy allowed to capture the dynamic behavior of methane dehydrogenation on M₁₃ clusters, revealing how variations in metal identity and adsorption energetics lead to distinct surface coverages and reaction behavior with temperature.