Hierarchical CaTiO3 nanowire-network architectures for H2 evolution under visible-light irradiation

Abstract

The development of new materials with hierarchical frameworks and tailored band structures is an attractive approach to efficiently photocatalytic hydrogen evolution. Here, we report a visible-light active calcium titanate (CaTiO3) photocatalyst with a hierarchical architecture constructed from single crystal nanowires, which was prepared by a one-pot hydrothermal reaction using polyvinyl alcohol (PVA) as structure directing agent. The hierarchical structure of the CaTiO3 samples involved single-crystal nanowires growing respectively along the [110], [11¯0] and [001] direction and intersecting each other perpendicularly which further featured a high specific surface area and oxygen vacancies. This material was able to split water into H2 under visible light irradiation. It was found that oxygen vacancies formed an impurity level at an energy level 0.95 eV below the conduction band acted as electron donors and promoted charge transport and separation.