Abstract
The reactivity and catalytic performance of MXenes in propane dehydrogenation (PDH) are highly dependent on their composition. This study explores modifying MXenes by substituting their X-layers with carbon, nitrogen, or a mix of both. Density functional theory (DFT) and microkinetic simulations show that these substitutions substantially alter the catalytic mechanism. Nitrogen substitution shifts the p-band center of oxygen active sites closer to the Fermi level, significantly lowering the energy barrier for the first C-H bond activation. Microkinetic analysis further confirms that nitrogen-substituted MXenes exhibit the highest turnover frequency (TOF) for propane conversion and propylene formation. The findings demonstrate that PDH reactivity can be precisely tuned by X-layer substitution, offering a strategy for optimizing MXene-based catalysts.