Coupling of rGO@α-MnO2 and rGO@TiO2 graphene modified catalysts: Enhancing photothermal synergistic catalytic oxidation performance of VOCs

VOCs pose a substantial threat to human health and the environment in confined spaces, and catalytic oxidation has emerged as a high-efficiency approach to achieving VOCs mineralization. A series of rGO@α-MnO 2 and rGO@TiO 2 composites were prepared via a one-pot hydrothermal method. The evaluation of the catalyst performance of rGO@α-MnO 2 , rGO@TiO 2 , and their coupling in VOCs (toluene, as a representative) degradation was conducted. It was found that the optimized 5%rGO@α-MnO₂ achieved 80% toluene conversion at a low temperature of 120 °C. 1%rGO@TiO₂ delivered the optimal long-term photocatalytic performance with a stable toluene degradation efficiency of 37.6%～41.3%. The coupling results of 5%rGO@α-MnO 2 and 1%rGO@TiO 2 in toluene conversion demonstrated that the composite with a Mn/Ti molar ratio of 2:1 exhibited optimal photothermal catalytic performance, maintaining a nearly 100% toluene removal efficiency during a 60 h continuous reaction. The introduction of rGO effectively modulates the photoresponse behavior, redox capacity, and surface physicochemical characteristics of metal oxide matrices. Such structural integration yields intimate coupling of photocatalytic and thermocatalytic pathways, which remarkably enhances the intrinsic catalytic activity of the hybrid catalyst system. This work provides insight into enhancing the catalytic performance of environmentally friendly and cost-effective catalysts for low-temperature catalytic degradation of VOCs.