DFT Study Of Catalytic Dehydrogenation Of Toluene On Different Platinum Surfaces

The purpose of this research is to investigate the catalytic oxidation of toluene on platinum surface by using density functional theory(DFT)calculations.The chemisorption of toluene on Pt(111),(100),(110),(211)and(200)surfaces were investigated on the basis of thermodynamics.Strong aromatic ring-surface interaction was observed which led to deformation in the shape of toluene over some surfaces.Toluene exhibited stable geometry and was evidently adsorbed on Pt(111)and Pt(100)surfaces.Further calculations were performed to elucidate the catalytic behavior on toluene decomposition on the Pt(111).Transition state search were carried out to find activation barriers related to every dehydrogenation step from both the methyl group and the aromatic ring of toluene.The C-H bonds in the methyl group are found to be weaker than that of the aromatic ring.The sequential steps for the dehydrogenation reaction in the methyl group of toluene(C6H5CH3??C6H5CH2?C6H5CH?C6H5C)are exothermic reactions with lower activation barriers.The dehydrogenation steps of the aromatic ring of toluene are highly endothermic reactions with relatively higher activation energies.The lower activation barriers in the methyl group favors toluene dehydrogenation on Pt(111)surface more than the dehydrogenation of the aromatic ring.Our calculations were overwhelmingly supported by various bond lengths to clarify catalytic activity of different Pt surfaces.