Quantification of the Synergetic Contribution of a Buried WO3/TiO2 Heterojunction to Photocatalytic Activity

Abstract

The tungsten trioxide/titanium dioxide (WO3/TiO2) heterojunction is archetypical in photocatalysis, with demonstrated synergetic properties despite some controversy around the predominant band model in these systems. The current work is a systematic study that quantified the synergetic contribution of TiO2 coating thickness to the enhancement of photocatalytic activity in nanostructured WO3/TiO2 heterojunction films. The films were produced from atomic layer deposition and chemical vapour deposition techniques and their photocatalytic activity was correlated with transient adsorption properties upon TiO2 coating thickness. The study allowed to identify an optimum thickness range within 21–40 nm, which showed the greatest contribution of the heterojunction. The outputs of this research have strong implications to heterojunction materials design for practical applications.