Dissociative adsorption of molecular hydrogen onto Pt6 and Pt19 platinum clusters located on the tin dioxide surface: Quantum-chemical modeling

It is suggested that, for the operation of platinum catalysts based on tin dioxide in air hydrogen fuel cells, hydrogen spillover (migration) leading to a change in the electron and proton contributions of the catalyst conductivity is of crucial importance. The hydrogen adsorption, dissociation, and...

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Bibliographic Details
Published in:Russian journal of inorganic chemistry 2011, Vol.56 (10), p.1579-1588
Main Authors: Zyubina, T. S., Zyubin, A. S., Dobrovol’skii, Yu. A., Volokhov, V. M., Arsatov, A. V., Bazhanova, Z. G.
Format: Article
Language:English
Subjects:
Adsorption
Chemistry
Chemistry and Materials Science
Clusters
Energy of dissociation
Inorganic Chemistry
Migration
Platinum
Surface chemistry
Theoretical Inorganic Chemistry
Tin dioxide
Tin oxides
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Summary:It is suggested that, for the operation of platinum catalysts based on tin dioxide in air hydrogen fuel cells, hydrogen spillover (migration) leading to a change in the electron and proton contributions of the catalyst conductivity is of crucial importance. The hydrogen adsorption, dissociation, and migration in the platinum-tin dioxide-hydrogen system surface have been modeled by the density functional theory method within the generalized gradient approximation (GGA) under periodic conditions using a projector-augmented plane-wave (PAW) basis set with a pseudopotential. It has been demonstrated that the adsorption energy of a hydrogen molecule onto a platinum cluster increases from 1.6 to 2.4 eV as the distance to the SnO 2 substrate decreases. The calculated Pt-H bond length for adsorbed structures is 1.58–1.78 Å. The computer modeling has demonstrated that: (1) the hydrogen adsorption energy on clusters is higher than on the perfect platinum surface; (2) dissociative chemisorption onto Pt n clusters can occur without a barrier and depends on the adsorption site and the cluster structure; (3) the adsorption energy of hydrogen onto the SnO 2 surface is higher than the adsorption energy onto the platinum cluster surface: (4) multiple H 2 dissociation on the tin dioxide surface occurs with a barrier; (5) the dissociation adsorption of hydrogen molecules onto the platinum cluster surface followed by atom migration (spillover) is energetically favorable.
ISSN:0036-0236
1531-8613
DOI:10.1134/S0036023611100287