WO3–reduced graphene oxide composites with enhanced charge transfer for photoelectrochemical conversion

Abstract

Hybrid structures between semiconducting metal oxides and carbon with rational synthesis represent unique device building blocks to optimize the light absorption and charge transfer process for the photoelectrochemical conversion. Here we demonstrate the realization of a WO₃–reduced graphene oxide (RGO) nanocomposite via hydrothermal growth of ultrathin WO₃ nanoplates directly on fluorine-doped tin oxide (FTO) substrates, followed by in situ photo-reduction to deposit RGO layers on WO₃ nanoplate surface. Photoanodes made of the WO₃–RGO nanocomposites have achieved a photocurrent density of 2.0 mA cm⁻² at 1.23 V vs. reversible hydrogen electrode (RHE), which is among the highest reported values for photoanodes based on hydrothermally grown WO₃. Electrochemical impedance spectroscopy reveals that the increase of photoactivity is attributed to the enhanced charge transfer by the incorporation of RGO, thus suggesting a general approach for designing other metal oxide–RGO hybrid architectures.