A reduced graphene oxide/bismuth vanadate composite as an efficient piezocatalyst for degradation of organic dye

Reduced graphene oxide (rGO)/bismuth vanadate (BiVO4) composites with varying rGO content (0, 1, 2, 3, and 5 wt%) were synthesized and explored for their piezocatalytic dye degradation performance. X-Ray diffraction (XRD) and Raman spectroscopy evidenced the co-existence of BiVO4 and rGO phases in all composite samples. The interfacial coupling between the BiVO4 and rGO phases in a typical rGO/BiVO4 composite was confirmed using transmission electron microscopy (TEM). The elemental oxidation states in a typical rGO/BiVO4 composite were identified using X-ray photoelectron spectroscopy (XPS). The piezocatalytic activity of all samples was analyzed by the use of a model dye named methylene blue (MB) using an ultrasonicator. Results demonstrate that the piezocatalytic activity greatly depends on the rGO content of the composite. The piezocatalytic dye degradation performance of the composites showed an initial increase with increment in rGO content up to 2 wt% followed by a decrease with further increment in rGO content. The best piezocatalytically active composite sample (2 wt% rGO/BiVO4) showed similar to 81% MB dye degradation as compared to pure BiVO4 (similar to 19%) under 180 min ultrasonication. Thus, the 2 wt% rGO/BiVO4 composite has promising piezocatalytic capability to be used for water remediation.