Ligand-assisted synthesis of novel π-SnS tetrahedrons for enhanced photocatalytic H₂ evolution from water

Abstract

Tin sulfide (SnS) is a potentially promising chalcogenide material for efficient solar energy conversion. In this study, pure π-SnS particles with a novel cubic phase were successfully synthesized by a simple one-pot solvothermal reaction method. The effects of solvothermal reaction time and amount of the ligand, hexamethyldisilazane (HMDS), on physical and photocatalytic properties were investigated. Field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and X-ray diffraction revealed that the obtained π-SnS consisted of tetrahedral particles with a high degree of crystallinity and exhibited a cubic phase. UV-Vis transmission spectra and photoluminescence (PL) revealed that the bandgap of π-SnS particles was about 1.62 eV. Importantly, the H₂ evolution capacity of π-SnS particles prepared with Tin-HMDS complexes was dramatically improved. About 12-fold and 23-fold larger amounts of H₂ were produced than the amounts produced by π-SnS particles prepared without HMDS and α-SnS particles with similar size, respectively. Post-annealing treatment further confirmed the existence of surface ligands and their importance for the photocatalytic activity of particles. X-ray photoelectron spectroscopy (XPS) revealed HMDS ligands instead of oleylamine molecules interacted with π-SnS particles.