Charge self-regulation over in-plane two-dimensional/two-dimensional hetero-cocatalyst for robust photocatalytic hydrogen generation.

An innovative charge self-regulation strategy is proposed to construct a strongly interacting 2D/2D ReS 2 -MoS 2 in-plane hetero-cocatalyst, which collectively enables the activation of H 2 O molecules and subsequent H 2 evolution. [Display omitted] • A in-plane 2D/2D ReS 2 -MoS 2 hetero-catalyst was developed via molten salt methods. • H 2 -evolution rate of TiO 2 can be greatly improved by ReS 2 -MoS 2 hetero-cocatalyst. • The high activity of ReS 2 -MoS 2 was due to the formed Re(4−δ)+ and S(2−δ)− sites. • A charge self-regulation mechanism of ReS 2 -MoS 2 was proposed. The rationally designing and constructing atomic-level heterointerface of two-dimensional (2D) chalcogenides is highly desirable to overcome the sluggish H 2 O-activation process toward efficient solar-driven hydrogen evolution. Herein, a novel in-plane 2D/2D molybdenum disulfide-rhenium disulfide (ReS 2 -MoS 2) heterostructure is well-designed to induce the charge self-regulation of active site by forming electron-enriched Re(4−δ)+ and electron-deficient S(2−δ)− sites, thus collectively facilitating the activation of adsorbed H 2 O molecules and its subsequent H 2 evolution. Furthermore, the obtained in-plane heterogenous ReS 2 -MoS 2 nanosheet can powerfully transfer photoexcited electrons to inhibit photocarrier recombination as observed by advanced Kelvin probe measurement (KPFM), in-situ X-ray photoelectron spectroscopy (XPS) and femtosecond transient absorption spectroscopy (fs-TAS). As expected, the obtained ReS 2 -MoS 2 /TiO 2 photocatalyst achieves an outperformed H 2 -generation rate of 6878.3 μmol h−1 g−1 with visualizing H 2 bubbles in alkaline/neutral conditions. This work about in-plane 2D/2D heterostructure with strong free-electron interaction provides a promising strategy for designing novel and efficient catalysts for various applications. [ABSTRACT FROM AUTHOR]