Adsorption and dissociation of molecular hydrogen on Pt/CeO_2 catalyst in the hydrogen spillover process: A quantum chemical molecular dynamics study

摘要

Ultra accelerated quantum chemical molecular dynamics method (UA-QCMD) was used to study the dynamics of the hydrogen spillover process on Pt/CeO_2 catalyst surface for the first time. The direct observation of dissociative adsorption of hydrogen on Pt/CeCh catalyst surface as well as the diffusion of dissociative hydrogen from the Pt/CeO_2catalyst surface was simulated. The diffusion of the hydrogen atom in the gas phase explains the high reactivity observed in the hydrogen spillover process. Chemical changes, change of adsorption states and structural changes were investigated. It was observed that parallel adsorption of hydrogen facilitates the dissociative adsorption leading to hydrogen desorption. Impact with perpendicular adsorption of hydrogen causes the molecular adsorption on the surface, which decelerates the hydrogen spillover. The present study also indicates that the CeO_2 support has strong interaction with Pt catalyst, which may cause an increase in Pt activity as well as enhancement of the metal catalyst dispersions and hence increasing the rate of hydrogen spillover reaction.