Synergistic effects of K addition and hydrogenation of TiO2 on photocatalytic hydrogen production under simulated solar light

Abstract

Herein, we report the photocatalytic performance of hydrogen production from water splitting over the TiO2 catalysts modified with K addition and hydrogenation. The results show that additive K in TiO2 can inhibit the phase transformation from anatase to rutile, and hydrogenation can induce oxygen vacancies and improve the photon absorption of TiO2. Simultaneously, we observe the formation of the KxTi8O16 nanoparticles on the surface of TiO2. Further investigations reveal that there exists the heterostructure between KxTi8O16 and anatase. Both the in situ formed KxTi8O16-anatase heterostructure and the hydrogenation-induced defects can enhance the light absorption and depress the fast recombination of photogenerated electrons and holes. Particularly, the former plays a more significant role in facilitating the separation of photogenerated charge carriers. Accordingly, the modified TiO2 catalysts show the enhanced photocatalytic performances, especially for 5KTH700, whose hydrogen production rate is ∼11 times higher than the unmodified TiO2. Our work provides a new strategy for design and synthesis of highly active photocatalysts for solar energy utilizations.