Interfacial electron modulation of 2D nanopetal ZnIn2S4 with edge-decorated Ni clusters for accelerated photocatalytic H2 evolution.

Heterostructure interfacial engineering between photocatalyst and co-catalyst to obtain an optimized electronic structure is a promising approach to improving their performance in the photocatalytic hydrogen evolution reaction (HER). In this work, two-dimensional nanopetal-like ZnIn2S4 (ZIS) with an adequately exposed active (110) edge facet-decorated Ni cluster heterostructure was prepared via chemical bath deposition, followed by photodeposition. In the catalyst preparation, the ZIS microstructure was modulated to sufficiently expose the active sites of the (110) edge for the HER, on which spontaneous interfacial engineering with an additional Ni cluster co-catalyst would be triggered via photodeposition in situ. The hydrogen production rate of the composite photocatalyst was excellent, at up to 26.80 mmol g-1 h-1 under simulated sunlight, which was 15.4 times greater than that of pristine ZIS. The optimized photocatalyst achieved a state-of-the-art apparent quantum yield of 61.68% at a single wavelength of 420 nm. Combined with systematic experimental characterization and density functional theory calculation, it was demonstrated that the separation and migration of charge carriers were significantly enhanced via the Ni cluster-induced interfacial electron redistribution, which contributed to the near-zero Gibbs free energy barrier and favored intermediate (*H) adsorption and desorption behavior, resulting in the superior photocatalytic performance. In summary, this work enables tuning of the interfacial electronic properties via spontaneous photodeposition of metallic cluster co-catalyst on the edge active sites, through which the separation of photogenerated charge carriers and surface redox reactions can be synergistically facilitated.