The photocatalytic H2O2 production is a sustainable and eco-friendly process. Bismuth vanadate (BiVO4 or BVO) is a promising photocatalyst with a low band gap energy. Reduced graphene oxide (rGO) is known for promoting the transport of charges and preventing the recombination of photogenerated electron–hole pairs. This study proposes a synthesis method based on an electrostatic self-assembly approach for functionalizing BVO with GO for photocatalytic H2O2 generation. Different amounts of GO loading on BVO have been taken to assess and optimize the quality of xrGO–BVO (where x = 0.5, 1, 2, and 4 wt %) composites for effective H2O2 generation. H2O2 shows stability under acidic conditions; hence, the effectivity of the xrGO–BVO was tested using acids with different strengths. 1rGO–BVO exhibited efficient H2O2 generation in the presence of oxalic acid, promoting two-electron O2 reduction reaction with a good cyclic stability. A photocatalytic flow reactor study has also been presented to assess the feasibility of continuous H2O2 generation.

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.