Efficient removal of TBBPA with a Z-scheme BiVO₄-(rGO-Cu₂O) photocatalyst under sunlight irradiation

In this study, reduced graphene oxide (rGO) was used to fabricate a Z-scheme BiVO₄-(rGO-Cu₂O) photocatalyst for the degradation of Tetrabromobisphenol A (TBBPA) under sunlight irradiation. The photocatalyst was synthesized using a three-step method BiVO₄-(rGO-Cu₂O) photocatalyst with an rGO loading of 1% and (rGO-Cu₂O) to BiVO₄ ratio of 50% achieved the best degradation effect for TBBPA removal. Electron paramagnetic resonance spectroscopy (EPR) confirmed that the charge transfer path of BiVO₄-(rGO-Cu₂O) follows that of Z-scheme photocatalysts. Moreover, the addition of rGO increases the charge transfer efficiency. High performance liquid chromatography-mass spectrometry (HPLC-MS) was used to detect and analyze intermediate products, allowing the proposal of the main degradation pathway of TBBPA. Photogenerated electrons of BiVO₄-(rGO-Cu₂O) were then transferred into the conduction band of Cu₂O. Cu₂O is located in the surface layer, which has the most effective contact area with pollutants, and therefore has a good outcome for the photocatalytic reduction of TBBPA. Photogenerated electrons (e^-) and hydroxyl radicals (∙OH) are the main factors affecting TBBPA degradation. The degradation process of TBBPA includes electron reduction debromination, hydroxylation, and β-cleavage. In our work, BiVO₄-(rGO-Cu₂O) was successfully synthesized to degrade TBBPA; this study brings forth a novel approach for the degradation of halogenated organic pollutants using a Z-scheme photocatalytic composite.