▎ 摘　　要

In this study, rGO/BiVO4 nanospheres and cubics were effectively synthesized using hydrothermal technique (with varied concentrations ranging from 0.5 to 2.5 wt%) to design a heterostructure photocatalysts. Ultraviolet visible absorption spectroscopy, photoluminescence (PL) spectroscopy, X-ray diffraction (XRD) spectroscopy, scanning electron microscope (SEM), and Fourier Transform infrared (FTIR) spectroscopy were used to investigate the optical properties, structural, morphological, bending and stretching vibrations of functional groups of heterostructure composites. Ultraviolet spectroscopy was used to measure the band gap energy of pure BiVO4 and rGO/BiVO4 (2.40-2.31 eV). Under visible photo-illumination (420 nm), the photocatalytic performance of methylene blue (MB & RhB) dyes degradation was studied. Among all samples, the 2.5% rGO/BiVO4 photocatalyst demonstrated the highest photocatalytic activity. Rate constant of pure BiVO4 spherical nanoparticles was also calculated by using simulation (COMSOL 5.3a) which was 0.00464 min(-1) as compared to experimental value 0.00656 min(-1) for MB and 0.00869 min(-1) as compared to experimental value 0.0079 min(-1) for RhB. The photocatalysis of MB and RhB dyes for five consecutive cycles demonstrated good recyclability, confirming the composite's reusability. [GRAPHICS]