Bismuth Vanadate Encapsulated with Reduced Graphene Oxide for Hydrogen Peroxide Generation

摘要

Hydrogen peroxide (H_2O_2), a strong oxidant, is considered as a highly value-added chemical due to its diverse applications. The conventional multi-step process for H_2O_2 production in the industrial setting is energy intensive, using reactants of explosive nature and expensive catalysts. A photocatalytic H_2O_2 production, in contrast, is a sustainable and eco-friendly process, requiring mostly water, dioxygen (O_2), and sunlight. The role of the photocatalyst is to provide the electron for the reduction of O_2 and holes for the release of hydrogen ion in water. The main challenge with this approach is the lack of an efficient photocatalyst, which can absorb light and transfer the energy to redox reaction. Bismuth vanadate (BiVO_4), a semiconductor with a low band gap energy (～2.4 eV), is known to be a promising photocatalyst. Moreover, reduced graphene oxide (RGO) is well-known for its role in promoting the separation and transport of charges, preventing the recombination of photogenerated electron-hole pairs. This study proposes a method of synthesizing a composite catalyst by functionalizing BiVO_4, via the encapsulation with RGO. The catalyst synthesis is optimized by varying the amount of graphene oxide (GO) loading on BiVO_4. This paper will summarize the structural, morphological, and photoelectrochemical characterization of these BiVO_4-RGO catalysts. Preliminary results have indicated that the H_2O_2 production is enhanced by 3-fold with the presence of RGO and BiVO_4 than BiVO_4 alone. The role of carbon doping in improving the light trapping and charge separation, resulting in the enhancement of photocatalytic H_2O_2 yield, will be examined.