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Dynamics of the Photogenerated Hole at the Rutile TiO2(110)/Water Interface: A Nonadiabatic Simulation Study
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posted on 2014-11-26, 00:00 authored by Georgios
A. Tritsaris, Dmitry Vinichenko, Grigory Kolesov, Cynthia M. Friend, Efthimios KaxirasHydrogen production in photoelectrochemical
cells constitutes an
important avenue toward carbon-free fuel. The most convenient process
for hydrogen production is the splitting of water molecules, which
necessitates a catalytic reaction involving a semiconductor. Here,
we introduce a framework for the study of photocatalyzed reactions
on semiconductor surfaces based on time-dependent density functional
theory that explicitly accounts for the evolution of electronically
excited states. Within this framework, we investigate the possibility
of hole-mediated splitting of molecularly adsorbed water on a representative
metal oxide surfacethe rutile TiO2(110). We find
that oxidative dehydrogenation of water is possible in synergy with
thermal effects at temperatures between 60 and 100 K only when defects
like Ti interstitials are present in the subsurface region. This study
presents a general computational strategy for describing photoexcited
semiconductor/adsorbate interfaces and also demonstrates that the
occurrence of water dissociation on the rutile TiO2(110)
surface depends sensitively on the local atomic environment and external
parameters such as temperature.