Effect of preparation methods and optical band gap of ZnO nanomaterials on photodegradation studies

Abstract Improving of photo-oxidative efficiency of ZnO has become of importance to meet the requirements of environmental protection. In this research, ZnO nanomaterials prepared by three different methods (thermal decomposition, precipitation and sol-gel-combustion using metal nitrate and different fuels (urea, oxalic acid and citric acid)). Various molar ratios of citric acid to salt used as variable parameter (0.50, 0.75, 1.00, 1.25, and 1.50). These nanomaterials were characterized by studying their structural, morphological, surface and optical properties. The photocatalytic activity was evaluated by photocatalytic degradation of Remazol Red RB-133 (RR) under UV-light irradiation. The obtained results showed that the photocatalytic efficiency was affected by preparation method, type and ratio of fuel to salt. The optimum is a gel precursor containing zinc nitrate and citric acid prepared in the molar ratio of 1. The highly active nanomaterial was applied for photocatalytic degradation of mixtures of two dyes – (RR) and Methylene Blue (MB).