Visible light induced H2 evolution on the spinel NiAl2O4 prepared by nitrate route

Abstract

This work is devoted to the preparation and characterization of the spinel NiAl2O4 prepared by nitrate route and its application for the hydrogen evolution under visible illumination. The X-ray diffraction revealed a cubic symmetry and a crystallite size of 40 nm, determined from the full width at half maximum. The oxide possesses a forbidden band of 1.84 eV and the transport properties indicate p-type conduction. The photo-electrochemical characterization gives a conduction band of −1.79 VSCE and the spinel is tested with success for the hydrogen formation under visible irradiation (29 mW cm−2). An evolution rate of 65 μL g−1 min−1 and a quantum yield of 0.15% are obtained within 30 min under optimal conditions (0.5 mg of catalyst/mL, pH ∼ 12 and 50 °C) in presence of SO32− as holes scavenger.