A Reusable Rgo/BiVO4 Photocatalyst for Hydrogen Peroxide Synthesis in Different Flow Systems

Abstract

The photocatalytic H2O2 production is a sustainable and eco-friendly process, requiring mostly water, oxygen, and sunlight. In previous study, bismuth vanadate (BiVO4), a semiconductor with a low band gap energy (~2.4 eV) was encapsulated with reduced graphene oxide (rGO) to promote the separation and transport of charges, preventing the recombination of photogenerated electron-hole pairs in BiVO4. 1% GO loading on BiVO4 was found to deliver effective H2O2 synthesis. H2O2 shows stability in acidic pH (~3), hence the effectiveness of the rGO/BiVO4 was tested under different types of acids. The order of efficiency of the acids is as follows: oxalic acid > phosphoric acid > formic acid > perchloric acid. This study involves the stability and reusability aspects of rGO/BiVO4 exhibiting significant H2O2 synthesis in the presence of oxalic acid catalyzing two-electron O2 reduction reaction. The photocatalytic H2O2 synthesis reaction following a zero-order kinetics, while the photocatalytic H2O2 decomposition following a first-order kinetics has been proposed as a mechanistic insight. A photocatalytic flow reactor study has also been evaluated to assess the feasibility of H2O2 generation in different reactor systems. Photocatalytic performance of rGO/BiVO4 composite was analysed in batch as well as flow reactor conditions.