Current applications of functionalized reduced graphene oxide-based semiconductors for photocatalytic removal of pollutants from wastewater: a review

Abstract

This review explores recent developments in the synthesis and application of amine-functionalized composites based on reduced graphene oxide (rGO) for photocatalytic pollutant degradation. Traditional photocatalysts, such as TiO₂, ZnO, and Fe₂O₃, often exhibit high crystallinity and photosensitivity, poor surface adsorption capacity, and limited visible-light responsiveness, leading to suboptimal photocatalytic efficiency. rGO enhances the photocatalytic performance of these materials by reducing the band gap, increasing electron–hole (e-/h⁺) separation rates, and expanding specific surface areas. Functionalizing rGO with amino groups improves the mechanical and thermal stability of hybrid nanocomposites, thereby maintaining a higher surface area and enhancing catalyst stability. Composites like rGO-ZnO, CuS-frGO, and AgBr@GN exhibit superior photocatalytic activity in degrading organic pollutants. This also review investigated the design and performance enhancements of rGO-based semiconductor nanocomposites, discussing how rGO improves electron mobility, reduces electron–hole recombination, and facilitates interactions with pollutants through π-π interactions. Fine-tuning rGO content and structure has led to significant improvements in photocatalytic efficiency, making these composites promising for commercial water purification. However, challenges such as synthesis methods, environmental impact, and real wastewater testing remain. Continued research and development are crucial for addressing these challenges and realizing the full potential of rGO-based photocatalysts in practical water purification systems.