Photocatalytic activities of hydrothermally synthesised ZnO nanorod films in synergism with visible light have been studied. Influence of each of the synthesis parameters, like concentration of precursor solution, relative concentration of hexamine and zinc nitrate, growth time, growth temperature, pre–growth seeding, post–growth annealing, concentration and pH of the contaminant suspension, and light source have been investigated. Appraisal of photocatalytic efficiencies of all the synthesised samples have been done on degradation of aqueous Methylene Blue (MB) solution under artificial/ambient light. Maximum photocatalytic activities were obtained when ZnO nanorods were synthesised with equimolar concentration of 10 mM hexamine and zinc nitrate grown for 15 hr at 90°C with post–synthesis annealing at 250°C in air. Solar irradiation was found more effective than artificial white light while the activity increased exponentially with pH value of the contaminant suspension.
Keywords: hydrothermal synthesis, ZnO nanorods, zinc oxide, photocatalytic activities, parameters, visible light, solar irradiation, nanotechnology, visible light photocatalysis, nanorod films, methylene blue, hexamine, zinc nitrate, artificial white light