Molecular simulation of methane dehydrogenation on Pd-based catalysts

The study of the mechanism of methane dehydrogenation on Pd-based dimer catalyst can provide a guidance for the design and selection of catalyst on methane combustion. The processes of methane dehydrogenation on three Pd-based dimer catalysts (Pd₂, PdPt and PdNi) are investigated using the density functional theory (DFT) calculation under the M06L/6-311++G(d, p)+SDD//M06L/6-311G(d, p)+LANL2DZ level. The energy barrier (E_b), activation energy (E_a), and reaction rate constant (k) of methane dehydrogenation on Pd₂, PdPt and PdNi are compared. The results indicate that CH₂→CH is the rate-determining step (RDS) for methane dehydrogenation on dimer Pd₂, while CH₃→CH₂ is the RDS on PdPt and PdNi; the catalytic activity for methane dehydrogenation on Pd-based dimer catalyst follows the order of PdPt > Pd₂ > PdNi; the anti-carbon performance follows the order of PdNi > Pd₂ > PdPt. PdPt is suitable for those cases requiring higher catalytic efficiency, while PdNi catalyst is suitable for large-scale industrial production due to the good anti-carbon property.