Protruding Pt single-sites on hexagonal ZnIn2S4 to accelerate photocatalytic hydrogen evolution

An alternative approach to defect-trapped Pt single-sites on a semiconductor is reported. Here, protruding Pt sites inhibit charge recombination and cause a tip effect which enhances H-2 evolution yield rates with minimal co-catalyst loading. Single-site cocatalysts engineered on supports offer a cost-efficient pathway to utilize precious metals, yet improving the performance further with minimal catalyst loading is still highly desirable. Here we have conducted a photochemical reaction to stabilize ultralow Pt co-catalysts (0.26 wt%) onto the basal plane of hexagonal ZnIn2S4 nanosheets (Pt-SS-ZIS) to form a Pt-S-3 protrusion tetrahedron coordination structure. Compared with the traditional defect-trapped Pt single-site counterparts, the protruding Pt single-sites on h-ZIS photocatalyst enhance the H-2 evolution yield rate by a factor of 2.2, which could reach 17.5 mmol g(-1) h(-1) under visible light irradiation. Importantly, through simple drop-casting, a thin Pt-SS-ZIS film is prepared, and large amount of observable H-2 bubbles are generated, providing great potential for practical solar-light-driven H-2 production. The protruding single Pt atoms in Pt-SS-ZIS could inhibit the recombination of electron-hole pairs and cause a tip effect to optimize the adsorption/desorption behavior of H through effective proton mass transfer, which synergistically promote reaction thermodynamics and kinetics.

Automated summary

An alternative approach involving protruding Pt sites on a semiconductor has been developed to enhance H2 evolution yield rates. By stabilizing ultralow Pt co-catalysts onto nanosheets, the protruding Pt single-sites promote reaction kinetics and provide a cost-efficient pathway for solar-light-driven H2 production.