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Sequential hydrogen dissociation from a charged Pt 13 H 24 cluster modeled by ab initio molecular dynamics
Author(s) -
Meng Qingguo,
May P. Stanley,
Berry Mary T.,
Kilin Dmitri
Publication year - 2012
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.24301
Subject(s) - dissociation (chemistry) , chemistry , hydrogen , molecular dynamics , cluster (spacecraft) , density functional theory , ab initio , hydrogen atom , atomic physics , catalysis , chemical physics , desorption , platinum , computational chemistry , physics , biochemistry , alkyl , organic chemistry , adsorption , computer science , programming language
Platinum is one of the most valuable catalysts that have been used in the catalytic fields of hydrogenation, fuel‐cell technologies, and photocatalytic water splitting. In this work, the dissociative chemisorption of hydrogen in a molecular form on a Pt 13 H 24 cluster with cuboctahedral symmetry ( O h ), which has one center Pt atom and side 12 Pt atoms (each bonded by two hydrogen), is investigated by using first‐principles density functional theory calculation. After computing geometry optimization on the Pt 13 H 24 cluster, the equilibrium distances of PtPt and PtH are inspected. Two nonequilibrium modifications, for example, addition of electrons and heat treatment were applied on the cluster, with the aim to simulate the experimental reaction of hydrogen on the Pt 13 H 24 cluster. An ab initio molecular dynamics (MD) is simulated after the cluster is charged and heat treated at high temperature to compute the trajectory for the positions of all the atoms. The computation results reveal that H 2 desorption is observed during the MD simulation, and higher temperature is beneficial to the H 2 desorption. An elementary hydrogen evolution mechanism on the charged Pt cluster can be established as 2H ads + + 2e − + Pt ads → [Pt ads H ads H ads ] → H 2 ↑ + Pt. A rate (fs −1 ) of hydrogen desorption from different cluster models is determined, together with the hydrogen dissociative activation energy as a function of total charge. © 2012 Wiley Periodicals, Inc.