Morphology engineering of ZnO nanostructures for enhanced photocatalytic efficiency of In(OH)3/ZnO nanocomposite

Abstract Very efficient and low-cost photocatalysts containing Indium hydroxide (In(OH)3) anchored on zinc oxide (ZnO) with various morphologies (e.g., hexagonal, pyramids, elliptic, etc.) were synthesized using a hydrothermal approach. The strong interaction between In(OH)3 and ZnO was investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), N2 adsorption-desorption, UV–vis diffuse reflectance spectroscopy (UV–vis DRS), and X-ray photoelectron spectroscopy (XPS). In(OH)3 particles grew directly on the ZnO surface and strongly interacted with it, which contributed to the excellent photocatalytic performance of ZnO. A possible formation mechanism of the In(OH)3/ZnO nanostructures was proposed. Experiments on photodegradation of methylene blue (MB) showed that the photocatalytic activity of the In(OH)3/ZnO nanocomposites correlated with the material morphology. The highest MB removal efficiency by the In(OH)3/ZnO hybrid photocatalysts was 90.5% after 120 min exposure to the visible light. The significant improvement of photocatalytic activity of In(OH)3/ZnO hybrid can be attributed to their special structural features, which allowed for an extended spectral response as well as for enhanced separation of photogenerated charge carriers. The design principles of this hybrid material apply to other metal-oxide systems to widen variety of advanced material systems with multifunctional properties useful for sensing and other advanced applications.