科研之友
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摘要
Hydrogen 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.
- 出版日期2014-11-27
