Fabrication and characterization of reduced graphene-BiVO₄ nanocomposites for enhancing visible light photocatalytic and antibacterial activity

Different BiVO₄ (BV) and reduced graphene/BiVO₄ nanocomposites photocatalysts were successfully prepared and used in the removal of MB and RhB dyes from aqueous solutions under indirect Sun light irradiation. The prepared samples were characterized by XRD, FTIR, SEM, EDS and TEM techniques. XRD, SEM and TEM analyses showed that the higher temperatures promote the particles growth and influence on the morphology and the structure of the BiVO₄ powders that tightly attached to the graphene surface. FTIR and EDS analyses confirmed the reduction of GO into RGO by the calcination of GO/BiVO₄ (GBV) nanocomposites at 250 °C. The band gap (E_g) results showed that increasing of the calcination temperature and graphene content were accompanied by a gradual decrease in the E_g till reaches 1.59 eV for 10GBV4-250 sample. The 10GBV4-250 nanocomposite was found to give the best results among the prepared photocatalysts; it removes MB molecules after 30 min and RhB molecules after 50 min. The kinetic studies showed that the photodegradation follows the pseudo-first-order kinetic behavior. The prepared photocatalysts exhibited good photocatalytic stability and reusability under indirect Sun light irradiation. The results of antibacterial activities showed that the nanocomposites are more effective in destroying three bacterial strains and the sample 10GBV4-250 gives the best results.