Formation of urchin-like ZnO nanostructures by sol-gel electrophoretic deposition for photocatalytic application

Abstract

Currently, more attentions have been paid to the design and synthesis of three dimensional nanostructures. ZnO urchin-like shapes assembled by nanoparticles are grown on FTO glass substrates by sol-gel electrophoretic deposition of a colloidal sol containing zinc acetate (ZAD), triethylamine (TeA), and methanol. Based on observations from a time-dependent morphology evolution process, a three-step sequential growth model is recommended. The formation of urchin-like ZnO nanostructures depends on the type of media, sol concentration, and molar ratio of TeA/ZAD. Importantly, strong structure-induced photocatalytic performance enhancement for the degradation of methylene blue is obtained by these ZnO nanostructures compared to traditional ZnO film. The large specific surface area (48.4 m2 g−1), strong light absorption ability, and nanoparticle shape affect the charge separation and transfer of urchin-like particles and hence enormously enhance the performance of photocatalyst. This work helps better understanding of the urchin-like shapes formed during sol-gel electrophoretic deposition and introduces an efficient way to enhance the photocatalytic efficiency of ZnO by changing the morphology.