Light-induced In-situ Ti3+Formation in TiO2Nanosheets for Photocatalytic Hydrogen Evolution

Abstract

TiO2 has been the benchmark semiconductor for the production of photocatalytic H2 from aqueous media (with and without sacrificial agent). On TiO2 surfaces, the photocatalytic H2 evolution reaction in aqueous environments is kinetically severely hampered. To overcome this limitation and reach reasonable H2 generation rates, a well-elucidated approach is the use of noble metal co-catalysts. In contrast to costly noble metal approaches, it recently has been reported that titania reduction treatments can lead to a noble-metal-free photocatalytic H2 generation. So-called "grey"titania due to Ti3+ states shows intrinsically activated photocatalytic H2 evolution [1-3]. The present work demonstrates the feasibility to use in-situ photoinduced reduction to create Ti3+ states that act as intrinsic catalyst and activate hydrothermal synthetized anatase nanosheets for H2 generation to mediate the transfer of photo-induced charge carriers to the electrolyte.