Photocatalytic properties of solution combustion synthesized ZnO powders using mixture of CTAB and glycine and citric acid fuels

Abstract

Zinc oxide (ZnO) powders have been prepared by solution combustion synthesis method using combination of cetyltrimethylammonium bromide (CTAB) with glycine and citric acid fuels. The combustion behavior, phase evolution, microstructure, optical properties and photocatalytic performance were compared by thermal analysis, X-ray diffractometry, electron microscopy, and diffuse reflectance and photoluminescence spectrometry techniques at various fuel to oxidant ratios (ϕ = 0.5, 0.75, 1 and 1.5). Single phase and well-crystalline ZnO powders were directly formed regardless of fuel type and fuel content. The higher specific surface area and pore volume of the as-combusted ZnO powders using mixture of CTAB and citric acid fuels increased with fuel content. The lower band gap energies (3.10–3.16 eV) of the as-combusted ZnO powders in the presence of glycine fuel were attributed to their lower crystallinity, as confirmed by higher visible emission in photoluminescence spectra. The higher photodegradation of methylene blue under ultraviolet light irradiation was achieved by the as-combusted ZnO powders by using CTAB-citric acid mixed fuels, due to their good crystallinity and higher specific surface area.