Nanostructured electroless Ni deposited SnO2 for solar hydrogen production

Abstract

Herein, Ni-decorated SnO₂ (Ni@SnO₂) nanostructures have been synthesized using SnO₂ as a matrix via a simple electroless deposition method for the generation of hydrogen, a potent near-future fuel. XRD analysis confirmed the generation of rutile SnO₂ in Ni@SnO₂. FESEM and FETEM imaging exhibited the formation of SnO₂ nanoparticles with a size of 10–50 nm, which are deposited with Ni nanoparticles (5–7 nm) and intermittent films (thickness 1–2 nm). The associated EDS elemental mapping validated Ni deposition on the surface of the SnO₂ nanoparticles, further supplemented by FTIR, Raman and XPS analysis. Slight red shifts in the band gaps of the Ni@SnO₂ nanostructures (in the range of 3.53–3.65 eV) compared to the pristine SnO₂ nanoparticles (3.72 eV) were observed. Also, intensity quenching of the band gap and associated defect peaks were observed in PL analysis. The Ni@SnO₂ nanostructures were used as photocatalysts and exhibited proficient hydrogen evolution. Among the samples, the 0.3 wt% Ni@SnO₂ nanostructures showed the greatest hydrogen evolution, i.e., ∼50 μmol g⁻¹ h⁻¹ under visible light irradiation versus pristine SnO₂ (8.5 μmol g⁻¹ h⁻¹) owing to the enhanced density of active sites and effective charge separation. It is noteworthy that the hydrogen evolution is much better as compared to earlier reports of Pt-doped-SnO₂ based materials.