Study of the growth mechanism of tungsten oxide onto graphene oxide via microwave-assisted approach

Abstract

Photoanodes based on W-BiVO4/WO3 heterojunctions are promising for photoelectrochemical water splitting. However, they have important drawbacks, such as limited charge transfer, photocorrosion and recombination. A strategy to enhance the heterojunction efficiency is enhancing the conductivity and surface area by coupling WO3 with graphene. Several routes have been used to synthesize WO3 onto graphene, including the microwave-assisted synthesis; which is a technique that allows a drastic reduction of the time and energy consumption, as well as give rise to unique interface properties at the heterojunction, due to the unique interaction of the microwaves with the reactional species. However, the microwave-assisted procedures reported so far for WO3/graphene synthesis do not provide enough information regarding the microwave parameters, therefore, most of them are not reproducible. Thus, the present project aims to elucidate the growth mechanism of WO 3 /graphene performinga deep structural and morphological investigation of early stages of the reaction, using techniques, such as High-resolution transmission electron microscopy (HRTEM) and high-angle annular scanning transmission electron microscopy (HAADF-STEM) studies combined with energy-dispersive X-ray spectroscopy (EDXS). Also, we aim to detect the reaction by-products via high-performance liquid chromatography (HPLC/MS). Then, we will be able to develop highly controlled architectures in a systematic way to find the best conditions to enhance the performance of photoactive electrodes.