Facile in-situ synthesis of a zinc oxide crystals/few-layered graphene flake composite for enhanced photocatalytic performance

An efficient mutilayer graphene-based semiconductor catalyst of reduced graphene oxide flakes decorated with zinc oxide crystals (ZnO/RGO) has been successfully synthesized in-situ using a facile low-temperature solution procedure. Zinc acetate was used as a single precursor with dimethyl sulfoxide acting as the mixing agent. The photocatalytic materials were then characterized using scanning electron microscope and X-ray diffraction patterns, as well as Raman, FT-IR, XPS and UV–vis spectroscopies. The ZnO crystals were found covalently boned onto reduced graphene flakes though direct Zn[sbnd]O[sbnd]C path, and this could allow photogenerated electrons quickly transfering from the ZnO to RGO and thereby efficiently lengthened the lifetime of the photogenerated charge carriers from the ZnO crystals. This result has been further confirmed by surface photovoltage spectrum studies. Compared to pure ZnO, small amount of 0.15 mg/ml ZnO/RGO hybrid had exhibited superior photocatalytic activity and reproducible catalytic efficiency onto 2 × 10⁻² mg/ml Rhodamine B dye in consecutive uses. The detailed formation of synthesis and characterization as well as photocatalytic mechanisms have also been explored.