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

Abstract

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 ∼81% MB dye degradation as compared to pure BiVO₄ (∼19%) under 180 min ultrasonication. Thus, the 2 wt% rGO/BiVO₄ composite has promising piezocatalytic capability to be used for water remediation.