Hybrid Dot–Disk Au-CuInS₂ Nanostructures as Active Photocathode for Efficient Evolution of Hydrogen from Water

The synthesis of hybrid 0D-2D dot–disk Au-CIS heterostructures is enabled through nucleating wurtzite ternary I–III–VI CuInS₂ (CIS) semiconductor nanostructures on cubic Au particles via thiol-activated interface reactions. Chemistry of formation of these unique hybrid metal–semiconductor nanostructures is established by correlating successive X-ray diffraction patterns and microscopic images. Furthermore, these nanostructures are explored as an efficient photocathode material for photoelectrochemical (PEC) production of hydrogen from water. Although CIS nanostructures are extensively used as PEC active materials for solar-to-hydrogen conversion, the coupled structures with Au for their exciton–plasmon coupling is observed in producing a higher photocurrent with efficient evolution of hydrogen. In the comparison of materials properties, it is observed that the cathodic photocurrent, onset potential, and the half-cell solar-to-hydrogen efficiency (HC-STH) are recorded to be superior to all CIS-based photocathodes reported up to the current time. These results suggest that designing proper heterostructured functional materials can enhance the hydrogen production in the PEC cell and would be helpful for the ongoing technological needs for a greener way of generating and storing hydrogen energy