Bidirectional carrier channels boost photocatalytic hydrogen evolution over NiO/Cd_0.7Mn_0.3S/Ti₃C₂T_x ternary...

Hydrogen evolution reaction (HER) driven by solar energy has attracted considerable attention due to its outstanding efficiency, environmental compatibility, and sustainability. Regrettably, the sluggish progress of the HER and the limitations in charge separation efficiency impede its practical photocatalysis. Herein, a two-step electrostatic self-assembly approach is adopted to construct NiO/Cd_0.7Mn_0.3S/Ti₃C₂T_x (NO/CMS/TCT) ternary heterojunction with bidirectional carrier channels for boost photogenerated separation and oriented carrier accumulation. As a result, optimally configured 4% NiO/Cd_0.7Mn_0.3S/25% Ti₃C₂T_x realized HER activity of 15 mmol·h^-1·g^-1, which is 68, 15, 68 and 2.3 times higher than that of the pristine NiO, Cd_0.7Mn_0.3S, Ti₃C₂T_x and 4% NiO/Cd_0.7Mn_0.3S, respectively. In-situ ESR, KPFM and DFT simulations confirm the underlying working mechanism of integrated bidirectional carrier channels formed by the heterojunction (NO/CMS) and Schottky junction (CMS/TCT), enabling efficient spatial separation and oriented accumulation of carriers, thereby enhancing overall photocatalytic hydrogen production. The proposed strategy offers fundamental insights into the mechanisms of carrier channel integration, paving the way for developing more advanced photocatalysts.