Fabrication of Conducting Polymer-Polyoxometalate Hybrid Photoanodes for Highly Efficient Water Splitting

Abstract

Tungsten oxide (WO3) is regarded one of the most promising photoanode for solar water splitting due to its intrinsic stability, environmental compatibility, a moderate hole-diffusion length (150-500 nm), and efficient electron transport. However, there are some limitations to be practically applied such as high recombination rate of photogenerated excitons, insufficient quantum efficiency and low absorption coefficient. To address such problems, in this study, we modified the WO3 surface with polyoxometalate (POM) water oxidation catalysts (WOCs) and conducting polymers by a simple electropolymerization method. We have tested three different conducting polymers such as polypyrrole (PPy), polyaniline (PANi) and poly(3,4-ethylenedioxythiophene) (PEDOT). We found that the photoelectrochemical performance of WO3 was significantly improved by the modification, possibly due to the increased visible light absorption and selective and efficient hole transport across the conducting polymer film, and improved charge transfer across the solid-electrolyte interface by the introduction of WOCs.