In-Situ Growth of MgO@rGO Core-Shell Structure via CO2 Thermal Reaction for Enhanced Photocatalytic Performance

Degradation of organic pollutants in wastewater is crucial for global environmental health. Semiconductor-based photocatalytic technologies have received widespread attention due to their ability to directly utilize solar energy, produce no secondary pollution, and offer long-lasting functionality. However, current photocatalyst preparation technologies face issues such as complex manufacturing processes, low efficiency, and the need for various additives. Therefore, this work proposes a simple and eco-friendly method to in-situ growth of reduced graphene oxide (rGO) onto magnesium oxide (MgO), forming a MgO@rGO core-shell structured photocatalyst through CO₂ thermal reaction process. After systematic study, the incorporation of rGO onto MgO core greatly extends the light absorption range from ultraviolet (UV) to visible wavelength, enabling substantially enhanced light capture and photoexcited carriers. Additionally, the core-shell heterojunction with a built-in electric field at the interface between MgO and rGO facilitates distinctly the separation and migration of the photogenerated charges. This structure-induced synergistic effect boosts the photocatalytic performance of MgO@rGO by a factor of 1.7, 4.1, 41.8, and 6.4, compared with MgO (stripped), MgO (pure), rGO, and commercially used TiO₂, respectively. This work provides a simple and effective strategy for designing advanced functional nanocomposites to address environmental problems.