In situ fabrication of all amorphous TiO2-coupled-MoSx photocatalysts for on-demand photocatalytic hydrogen production by using UV light†

Intergrating in situ fabrication of photocatalysts with on-demand photocatalytic H₂ evolution from water splitting holds immense promise for enhancing the H₂ utilization efficiency. Herein, all amorphous TiO₂-coupled-MoS_x photocatalysts (a-TM) are in situ fabricated by hydrolyzing the Ti precursor followed by photochemical reduction of (NH₄)₂MoS₄ in the reaction solution for on-demand photocatalytic H₂ evolution reaction (HER). Thanks to the intimate contact between a-TiO₂ and the a-MoS_x cocatalyst, as well as abundant active sites on the a-MoS_x cocatalyst, the photogenerated electrons can rapidly transfer from the excited a-TiO₂ to the well-interconnected a-MoS_x, leading to efficient charge separation, thereby greatly promoting the kinetics of the HER. The as-fabricated a-TM2 with 2 mol% a-MoS_x exhibits the highest H₂ evolution rate of 696.2 μmol h⁻¹ under UV light, 2.7 times higher than that of benchmark P25 loaded with a 2 mol% a-MoS_x cocatalyst (PM2). This work introduces a new concept of in situ fabricating semiconductor-based photocatalysts for on-demand photocatalytic HER at a large scale.