pH dependent ZnO nanostructures synthesized by hydrothermal approach and surface sensitivity of their photoelectrochemical behavior

Nanoparticulate ZnO materials were fabricated using microwave assisted hydrothermal synthesis from mixture of zinc acetate and ammonia at variable pH. The particle size and shape of resulting materials changes with the pH of precursor solution. The obtained nanoparticulate ZnO are of single phase nature with particle size ranging between 100 and 3000 nm, and are photoelectrochemically active in water oxidation upon UV illumination. Their photoelectrochemical activity, depends primarily on the ZnO particle surface orientation which changes with the particle size. The highest photoelectrochemical activity results from simultaneous presence of {0− 110} and {− 2110} oriented faces. The presence of {0001} oriented faces apparently suppresses the photoelectrochemical activity. The results indicate that the photoelectrochemical activity of ZnO is mainly related to a presence of {0−110} oriented surface.