A molecular precursor approach for the synthesis of hollow nanotubes and nanorods of antimonselite (Sb₂Se₃): an efficient electrocatalyst for hydrogen evolution reactions

We report the synthesis of an air-stable antimony(III) complex, [(BMImSe)(SbCl₃)]₂ (1), derived from 3-benzyl-1-methyl-(1<i>H</i>)-imidazole-2(3<i>H</i>)-selone (L). This complex, characterized through elemental analysis, NMR spectroscopy and single-crystal X-ray diffraction (scXRD), serves as an efficient single-source molecular precursor (SSP) for the facile fabrication of orthorhombic one-dimensional Sb₂Se₃ nanostructures. Comprehensive investigations using powder X-ray diffraction (PXRD), electron microscopy and diffuse reflectance spectroscopy (DRS) provided insights into the crystal structure, phase purity, morphology and bandgap properties of these nanostructures. Notably, reaction conditions significantly influenced the morphology, yielding hollow nanotubes (SbSe-1) under solventless decomposition and crystalline nanorods (SbSe-2) under solvent-assisted thermolysis. SbSe-1 nanotubes and SbSe-2 nanorods exhibited optical bandgaps of approximately 1.44 eV and 1.6 eV, respectively, indicating their potential as promising electrocatalysts. Furthermore, SbSe-1 hollow nanotubes demonstrated promising catalytic activity for the electrochemical hydrogen evolution reaction (HER). The catalyst achieved an overpotential of 424 mV at a current density of -10 mA cm^-2, with a Tafel slope of 81 mV dec^-1, and maintained excellent stability over 2000 cycles and 18 hours of chronoamperometric testing.