String and Ball-Like TiO2/rGO Composites with High Photo-catalysis Degradation Capability for Methylene Blue

Novel three-dimensional string and ball-like titanium dioxide/reduced graphene oxide, TiO 2 /rGO (STG) composites were prepared using a one-step hydrolysis process followed by a low-temperature hydrothermal treatment. The STG composites exhibited excellent photo-catalytic degradation performance for methylene blue owing to a good synergistic effect between TiO 2 and rGO. The STG composites with 1.0 wt% of rGO loading exhibited the highest removal rate of 86.0% for methylene blue and its reaction rate constant (5.27 × 10 −3  min −1 ) was much higher than those of pure string and ball-like TiO 2 (ST). In addition, the STG composites also showed an outstanding capability for the photo-catalysis degradation of other cationic dyes. In addition, a possible photo-catalytic degradation mechanism for the STG composite was postulated, in which \(^{ \bullet } {\text{O}}_{2}^{ - }\) and • OH were the main oxidizing groups. This work offers new insights into a better design and preparation of novel composite materials for the removal of organic dyes.