Novel Highly Active Anatase/Rutile TiO2 Photocatalyst with Hydrogenated Heterophase Interface Structures for Photoelectrochemical Water Splitting into Hydrogen

In the past few years, anatase/rutile TiO2 heterophase junction structures with highly efficient photo catalytic performance have been explored widely, while their activities are still unsatisfactory in solar-to-hydrogen energy conversion. In this study, a novel anatase/rutile TiO2 photoelectrode with hydrogenated heterophase interface structures (A-H-RTNA) was successfully designed and synthesized for the first time via hydrothermal synthesis hydrogenation branching growth. Structure characterization indicated that the hydrogenated interfaces between anatase branches and rutile TiO2 nanorod hold appropriate oxygen vacancies and Ti3+ and inferred that new energy levels of oxygen vacancy and Ti-OH lie below the band edge positions of conduction band and valence band of rutile TiO2 nanorod, respectively. The matching energy levels between anatase branches and hydrogenated rutile nanorod obviously reduce the recombination of the photogenerated carriers, resulting in a superior photoelectrochemical (PEC) performance. The hydrogen evolution rate on A-H-RTNA photoelectrode for PEC water splitting is 20 and 2.1 times those of unhydrogenated TiO2 nanorod arrays photoelectrode (RTNA) and surface-hydrogenated anatase/rutile TiO2 photoelectrode (H-A-RTNA), respectively. This work provides new insight into the effect of hydrogenated heterophase interface structure on the PEC properties of TiO2.