Ultrathin 1T/2H mixed phase MoS 2 decorated TiO 2 nanorod arrays for effective photocatalytic hydrogen evolution

Ultrathin mixed metallic phase (1T) and semiconducting phase (2H) MoS 2 nanosheet decorated TiO 2 nanorod arrays were prepared through a simple two-step hydrothermal method. By modulating the subsequent annealing conditions, the gradual phase transformation of MoS 2 from 1T to 2H was observed. The mixed phase MoS 2 shows superior photocatalytic hydrogen evolution to 2H phase MoS 2 and noble metal Pt. The distinguishable optical and photoelectrochemical behaviors of mixed phase MoS 2 and 2H phase MoS 2 reflect their different internal structures and charge transfer mechanisms. The existence of the abundant metal like 1T phase in the mixed phase MoS 2 accelerates the electron transport between TiO 2 and MoS 2 more effectively and decreases the recombination of electron–hole pairs, thus enabling preferable photocatalytic performance compared to 2H phase MoS 2 . The possible electron transfer mechanism between MoS 2 and TiO 2 is also illustrated.