Enhancing Free Cyanide Photocatalytic Oxidation by rGO/TiO(2) P25 Composites

Graphene-TiO(2) composites have been investigated in various photocatalytic reactions showing successful synergy compared to pristine TiO(2). In the present work, graphene oxide (GO) was synthesized by the Hummers method and then reduced graphene oxide-TiO(2) composites (rGO/TiO(2)) were obtained by an in situ GO photoreduction route. X-ray diffraction, FTIR, Raman, UV–vis DRS, and photoluminescence were the main characterization techniques. The obtained composites containing 1 and 3 wt.% rGO were evaluated in the cyanide (50 mg/L) oxidation and Au-cyanide complex (300 mg/L) degradation under UV-A light. The composites showed higher photocatalytic activity than TiO(2), mainly with the 1% rGO content. Cyanate and gold nanoparticles, deposited on the photocatalyst’s surface, were the main byproducts during the photocatalyst assessment. The improved photocatalytic activity of the composites was attributed to a higher rate of electron transfer and a lower rate of charge recombination due to the chemical interaction of rGO with TiO(2).