MoS2 and Ti3C2 Ensembles into TiO2 for Efficient Photocatalytic Hydrogen Evolution: Dual-Bonding Interactions and Capacitive Effect Trigger the Intrinsic Activities

Photocatalytic hydrogen evolution provides a sustainable and environmentally benign approach for large-scale solar energy conversion. How to substantially trigger the photocatalytic efficiency of semiconductor catalysts is still a challenging issue. Here, the sandwich-like hierarchical Ti3C2-TiO2-MoS2 (TM) composite is designed and synthesized by in situ growth of TiO2 and MoS2 nanosheets on MXene (Ti3C2) nanosheets. Consequently, the dual-cocatalyst-modified TiO2 photocatalyst can spark efficient photocatalytic H-2 evolution (4.3 times higher than pristine TiO2) and maintain excellent stability (>30 h). Specifically, the enhancement of photocatalytic efficiency can be originated from the promoted charge separation and migration through Ti-O-Mo and C-O-Ti dual charge transfer channels and enriched reactive active sites for proton reduction. More importantly, the capacitive properties of MoS2 and Ti3C2 can retain the photogenerated electrons at a long-lived charge-separated state, further improving the activity and stability. The potential of earth-abundant cocatalysts with capacitance effect to construct high-efficiency and low-cost photocatalysts is demonstrated.