Creating Multiple Parallel Internal Phase Junctions on ZnS Nanoparticles as Highly Active Catalytic Sites

Semiconductors based on earth-abundant elements such as ZnS are economic materials for energy conversion but are often limited by their light absorption property and fast charge recombination. Herein, a solvothermal preparation of ZnS nanocrystals with multiple internal phase junctions (MIPs) of alternating wurtzite and sphalerite phases, which exhibit dramatically enhanced photocatalytic hydrogen evolution reaction (HER) rate (6.9 mmol g⁻¹ h⁻¹) under simulated sunlight is reported. X-ray photoelectron spectroscopy indicates zinc atoms of different electronic environments on the surface of ZnS. The MIP-rich ZnS has substantially lower overpotential for electrocatalytic HER, probably due to the synergistic effect of easier H⁺ adsorption and enhanced H₂ desorption on the active sites. This work paves a new route of reforming nanomaterials to acquire intrinsically enhanced catalytic properties for energy conversion applications.