Decorating (001) dominant anatase TiO2 nanoflakes array with uniform WO3 clusters for enhanced photoelectrochemical water decontamination

A facile two-step chemical bath deposition (CBD) method has been developed for the preparation of uniformly crystalline anatase WO3/TiO2 array on FTO substrate. The synthesis starts from the hydrothermal growth of TiO2 array in a homogenous HCl aqueous solution containing stabilized titanium isopropoxide, NH4F and acetylacetone (AcAc). Electron microscopy and the XRD analysis suggest the addition of AcAc chelating agent can facilitate the preferential growth of interconnected and vertically aligned anatase (001) facets. While (101) dominant TiO2 bipyramid array may form without AcAc. The subsequent decoration of WO3 clusters on TiO2 array is achieved by post-depositing TiO2 array in (NH4)(2)WO4 aqueous solution followed with a calcination at 450 degrees C, the resultant WO3/TiO2 array shows a significantly elevated photocurrent performances owing to the high separation efficiency of charge carriers. The enhanced photoelectrocatalytic properties are explained by the efficient charge carrier separation at the heterojunction between WO3 and TiO2. A faster photoelectrochemical degradation of methylene under simulated sunlight further demonstrates the potential usefulness of WO3/TiO2 arrayed photoelectrocatalyst in solar-driven environmental purification and solar fuel synthesis.