The selective deposition of MoS2 nanosheets onto (101) facets of TiO2 nanosheets with exposed (001) facets and their enhanced photocatalytic H2 production

Abstract One of the challenging issues in photocatalytic hydrogen (H 2 ) production is to efficiently separate the photogenerated electron-hole pairs and require the enrichment of photogenerated electrons on the photocatalyst’s surface. Herein, a novel 2D-2D nanojunction of MoS 2 nanosheets (NSs) selectively deposited on the (101) facets of TiO 2 NSs with mainly exposed high-active (001) facets is prepared via a hydrothermal/annealing treatment combined with an photoreduction method using carbon fiber (CF) as templates. The obtained MoS 2 @TiO 2 composite (selective deposition) photocatalyst exhibits a greatly enhanced photocatalytic H 2 production activity at the optimal weight percentage of MoS 2 (15 wt%), exceeding that of pure TiO 2 NSs and MoS 2 @TiO 2 composites (random deposition) by 32 and 3 times, respectively. The superior photoactivity of MoS 2 @TiO 2 composites (selective deposition) is attributed to the synergistic promoting effects of the following factors: (i) the mainly exposed (001) facets of TiO 2 NSs with higher surface energy in MoS 2 @TiO 2 composites (selective deposition) facilitate the activation of water molecules and the photocatalytic reduction; (ii) the coexposed (101) and (001) facets can form a surface heterojunction within single TiO 2 NS, which is beneficial for the transfer and separation of charge carriers; (iii) the MoS 2 NSs are selectively deposited on the electrons-rich (101) facets of TiO 2 NSs, which can effectively reduce the charge carriers recombination rate by capturing photoelectrons. This study presents an inexpensive photocatalyst for energy conversion to achieve highly efficient H 2 evolution without noble metals.