Activation energy of hydrogen migration by relay in the O2/Pt19/SnO2/H2 + n H2O system |
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Authors: | T S Zyubina A S Zyubin Yu A Dobrovol’skii V M Volokhov |
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Institution: | 1. Institute of Problems of Chemical Physics, Russian Academy of Sciences, 1 prosp. Akad. Semenova, 142432, Chernogolovka, Moscow Region, Russian Federation
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Abstract: | In the framework of investigation of active and stable electrocatalysts for fuel cells, the hydrogen migration by relay with the consecutive formation of H2O molecules in the O2/Pt19/SnO2/H2·nH2O → O/Pt19/SnO2·nH2O + H2O system was simulated. The simulations were performed by the density functional theory (DFT) method with the generalized gradient adjustment (GGA=PBE) under periodic boundary conditions in the projector augmented plane wave (PAW) basis set with a pseudo-potential using the VASP program package. At the cathode on the platinum cluster surface, the oxygen molecules without a barrier form peroxide complexes that dissociate with an energy decrease. The protons transferred via the proton-conducting channels from the anode to cathode form first OH groups bound to the platinum cluster and then H2O molecules that are easily separated from the cluster (~0.2 eV). The proton transfer process proceeds by relay and involves several water molecules. |
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