Tungsten Oxide–reduced Graphene Oxide Composites for Photoelectrochemical Water Splitting

摘要

Photoelectrochemical (PEC) water splitting is the latest technology to produce hydrogen and electricity by using sunlight.The low bandgap of tungsten oxide (WO_3) enables it as a suitable candidate for PEC water splitting. Reduced graphene oxide(rGO) is a material having extra thin sheets and a very large surface area with extreme conductivity. Graphene oxide (GO)has been synthesized by using a modified Hummer’s method. Hydrothermal reduction of GO gives rGO. WO_3–graphenecomposites of different ratios have been prepared hydrothermally and then coated on indium tin oxide coated glass to makeelectrodes for water splitting. Various characterization techniques such as UV–visible spectroscopy, diffusion reflectancespectroscopy, X-ray diffraction, scanning electron microscopy, and linear sweep voltammetry (LSV) were used to study theabsorbance/reflectance, structure, morphology, and optical/electrical properties of prepared nanostructures. In addition,WO_3particles were distributed on the strong sheets of rGO randomly. The IV-measurements were taken of rGO/WO_3 electrodesunder dark environment (very minor current～250 nA) by using LSV. The electrodes exhibit maximum～450 μA under darkenvironment, while photocurrent initiates from 1.0 mA to 3.2mA under artificial sunlight. That is convincingly an exceptionalresult in the field of PEC cell.