Effectiveness of NiO in replacing Pt in the photochemical generation of hydrogen by (TiO2)(1-x)(NiO)(x)/Cd0.8Zn0.2S heterostructures

Abstract

Hydrogen evolution activity of semiconductor heterostructures of the type (TiO2)(1-x)(NiO)(x)/Cd0.8Zn0.2S has been investigated in detail to examine the role of NiO, used in the place of Pt by making use of nanoparticles and nanotubes of TiO2. Combination of NiO and TiO2 markedly changes the photocatalytic efficiency of the heterostructures. While the H-2 evolution activity increases smoothly with NiO mole farction up to x similar to 0.50, it increases further reaching a maximum at x similar to 0.83, yielding 1.6 mmol h(-1) g(-1) (AQY similar to 2.9%) with Na2S-Na2SO3 as sacrificial agents, under visible-light irradiation, and 6.84 mmol h(-1) g(-1) (AQY similar to 11.7%) and 13.5 mmol h(-1) g(-1) (AQY similar to 10%) with benzyl alcohol-acetic acid as sacrificial agents under visible and UV-visible light irradiation respectively. High hydrogen evolution activity to the tune of three times that yielded by equivalent Pt containg heterostructures has been attained, with a. NiO mole fraction of 0.83 in the heterostructures. (C) 2016 Elsevier Ltd. All rights reserved.