Enhanced photocatalytic degradation of naproxen in aqueous matrices using reduced graphene oxide (rGO) decorated binary BSO/g-C3N4 heterojunction nanocomposites

Abstract

Reduced graphene oxide-bismuth silicate-graphitic carbon nitride (rGO/BSO/g-C3N4) heterostructured nanocomposites was synthesised by wet-impregnation method. The morphology, microscopic, structural composition and optical properties of the nanocomposites were characterised, before and after modification of the materials with different amounts of rGO, using XRD, FTIR, TEM, HR-TEM, UV-Vis DSR, PL and BET analysis. The rGO/BSO/g-C3N4 nanocomposites are of high crystallinity. TEM images revealed the presence of wrinkled aggregates of rGO on layers of BSO and g-C3N4 sheets. A band gap energy of 2.34 eV was achieved in compositing, which results in increase in the composites absorption capacity and reduced photoluminescence emission. The reduced PL emission suggests decreased recombination of the photon-induced electron-hole pair, due to the decoration of rGO on the surface of the BSO/g-C3N4 composites. The rGO decoration of binary BSO/g-C3N4 composites improved the photocatalytic efficiency of the heterostructured rGO/BSO/g-C3N4 materials, with the 0.3wt% rGO/BSO/g-C3N4 nanocomposite achieving 97.70 and 77.52%, 90 min visible light irradiative degradation efficiency for naproxen in simulated and real wastewater samples, respectively. This efficiency is ascribed to excellent electron-hole separation, and good charge transfer occasioned by rGO decoration of BSO/g-C3N4. Photogenerated holes (h+) and .O2¯ radicals were noted as the main active species involved in naproxen degradation.