Enhanced photoelectrochemical performance of the hierarchical micro/nano-structured TiO2 mesoporous spheres with oxygen vacancies via hydrogenation

Abstract

Hierarchical micro/nano-structured TiO₂ mesoporous spheres with oxygen vacancies have been fabricated via a template-free strategy followed by hydrogenation and their photocatalytic performance has been explored. The hierarchical micro/nano-structured mesoporous spheres can act as a model architecture for efficient photoelectrochemical devices because they can simultaneously offer abundant catalytically active sites, excellent light-scattering characteristics and a highly conductive pathway for charge carriers collection. More importantly, oxygen vacancies are introduced onto the surface of TiO₂ and function as shallow donors. The presence of oxygen vacancies not only boosts the light absorption but also improves the electrical conductivities of TiO₂, thus enhancing the optical response and electron–hole separation. As a result, hierarchical micro/nano-structured TiO₂ mesoporous spheres with oxygen vacancies exhibit a remarkably enhanced photoelectrochemical performance.