Engineering of anatase/rutile TiO heterophase junction via in-situ phase transformation for enhanced photocatalytic hydrogen evolution.

Constructing effective interphase boundary is one of the efficient approaches for improving photocatalytic performances of semiconductor materials. In this work, an anatase/rutile-TiO (AR-TiO) heterophase junction with appropriate carbon content was successfully fabricated via an in-situ phase transformation process. The phase transformation started from the inner core of the nanoparticles and the area of phase interface between anatase and rutile was carefully controlled by regulating the activation temperature. The well-established type-II band alignment between two TiO phases with residual carbon as additional charge transfer intermediary which significantly improved the light-harvesting and photoinduced electron-hole pair separation. As a result, the optimal AR-TiO-550 catalyst (without adding commonly used Pt as co-catalyst) remarkably enhanced photocatalytic H generation (201 μmol h g), which was about 12-fold to that of P25. The AR-TiO-550 heterophase junction also showed long-term stability under simulated solar light irradiation. This research provides a new phase engineering route for developing high-efficient photocatalysts.