Improving Visible-light Responses and Electric Conductivities by Incorporating Sb2S3 and Reduced Graphene Oxide in a WO3 Nanoplate Array for Photoelectrochemical Water Oxidation

Abstract

The WO3, reduced graphene oxide (rGO), and Sb2S3 nanocomposite is firstly synthesized on a transparent conducting oxide glass by using a chemical bath deposition method coupled with a post-thermal treatment for catalysing the artificial photosynthesis under the framework of Z–scheme water splitting. Sb2S3 acts as the light absorber to mitigate poor visible light absorption and rGO serves as a electrically conductive layer to enhance the low quantum efficiency of WO3. An improved photocurrent density of 1.20mA/cm2 (at 1.23V vs. RHE) is obtained for the WO3/rGO/Sb2S3 electrode under AM 1.5G illumination, comparing to those for the WO3/Sb2S3 (0.27mA/cm2) and WO3 (0.05mA/cm2) electrodes. The negatively shifted onset potential of 0.35V vs. RHE is obtained when Sb2S3 and rGO are participated in the WO3 electrode, as compared with those of 0.42 and 0.45V vs. RHE for the WO3/Sb2S3 and WO3 electrodes, respectively. The improvements on the photoelectrochemical performances for the WO3/rGO/Sb2S3 electrode is primarily due to the broader light absorption and the enhanced electric conductivity. The results suggest that an efficient photocatalyst for water oxidation can be fabricated by carefully designing the composition of the nanocomposite with complementary optical and electrical preperties.