Enhanced photocatalytic organic dye removal performance of micro-nanostructured TiO2/graphene composites by using hydrochloric acid control its morphology

In this study, hydrochloric acid solution concentration-controlled micro/nanostructured mixed crystalline phase of TiO 2 coated with graphene was prepared via a one-step hydrothermal method to improve photocatalytic degradation of organic pollutants. By several characterization methods such as X-ray diffraction, scanning electron microscopy, transmission electron microscopy, we demonstrate that the mixed crystal phase of TiO 2 (2–5 nm) evenly distributed among the thin graphene layers when the concentration of hydrochloric acid solution is 3 mol/L. Compared with the bare P25, the photocatalytic activity and adsorption capacity of the composites were much enhanced, resulting from the involving of graphene sheet as chainmail, which facilitates the charge separation, suppresses the recombination of electron–hole pairs, and improves light conversion efficiency of catalysts. In addition, the degradation rate of micro/nanostructured TiO 2 /GN (graphene) composite under ultraviolet light irradiation was much higher than pure TiO 2 . After 40 min irradiation, the degradation rate of RhB reaches 97.2%. It is expected that this synthetic strategy may provide a new pathway for the fabrication of various GN-based hybrids with multi-dimensional micro/nanostructures.