The interface junction of composites is key to their fundamental properties and enhanced performance in many technologies. However, this is difficult to probe experimentally and is largely ignored in recent theoretical examinations of photocatalysts composed of TiO2 rutile-anatase composites. Computational advances permit detailed modeling of the structural, electronic and optical properties of composites. In this contribution, we focus on a model system of mixed-phase rutile-anatase TiO<sub>2</sub> and use density functional theory (DFT) to interrogate the key structural feature, namely, the rutile–anatase interface. We discuss its relationship to and effect on photogenerated charge localization, bulk band alignments, and defect formation. The interfacial region is disordered and distinct from rutile and anatase and contains low coordinated Ti sites and oxygen vacancies, both drivers of charge localization. The relaxations of the interface upon formation of excited electrons and holes determine the final location of charges which cannot always be predicted from bulk band alignments. We also investigate rutile modified with varying thickness of anatase and vice versa to explore the influence of the interface region in diffierent realisations of this phase junction. A detailed understanding of the interfacial phase junction between two materials lays the foundation for directed synthesis of highly active and efficient composite photocatalysts.

On the role of non-bulk interfacial structures in rutile-anatase TiO2 interfaces

253rd National Meeting (2017)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.