An Efficient Photocatalytic Material, rGO-TiO2, That Can Be Industrially Produced: Fabrication and Structural Characterization

As a well-known photocatalyst, TiO2 still suffers from rapid electron–hole recombination and limited visible light absorption. To overcome these challenges, the combination of graphene and TiO2 has been proposed. However, traditional methods such as ball milling and hydrothermal synthesis face limitations, including high energy consumption and complex procedures. Here, we develop a simple and industrially feasible method to prepare reduced graphene oxide (rGO)-coated TiO2 nanoparticles, referred to as rGO-TiO2 composites. The optimized rGO-TiO2 composites exhibit an enhanced photocatalytic degradation of rhodamine B (RhB) under simulated sunlight conditions, about 99.95% for 4% rGO-TiO2 within 80 min. The first-order reaction rate constant (k) of 4% rGO-TiO2 (0.0867 min−1) is 5.42 times higher than that of nano TiO2 (0.0135 min−1). The key reactive species involved in the degradation process are identified. Additionally, the effects of pH and NaCl concentration on the degradation efficiency of rGO-TiO2 are also investigated. The 4% rGO-TiO2 composite exhibits an excellent photocatalytic activity within the pH range of 3.87–11.89, and the NaCl concentration does not affect its photocatalytic efficiency. After characterization, the enhanced photocatalytic activity is ascribed to the introduction of rGO and the generation of surface oxygen vacancies (OV) and Ti3+ in TiO2 crystals.