Influence of Particle Size on Electrophotocatalytic Properties of Tungsten Trioxide Photoanodes

Abstract

The need for advanced wastewater treatment technologies has been highlighted by the widespread contamination of water sources with toxic and persistent organic chemicals. In this work, thin films of tungsten (VI) oxide (WO3) were prepared by spin-coating and Meyer rod coating nanoparticulate dispersions following a top-down approach through ball milling. The morphological properties of the layers were investigated by profilometry. The results showed that the surface area increased with an increase in milling time for the milled mixture, and, for the sample milled for 96 h, it showed a nine-fold increase compared to the commercial tungsten (VI) oxide powder. The electron microscopic images provided insight into the change in particle size and layer texture which comply with the morphological changes observed by profilometry. The influence of the particle size on the charge generation efficiency was investigated using photoanodes prepared from the studied suspensions. Two distinct formulations of different particle sizes were mixed in variable ratios, and we showed that multimodal coatings exhibit larger photocurrents than monomodal coatings. The main contribution of this work can be found in the economically inexpensive method of preparing thin films WO3.