Graphene-based nanocomposites in photocatalysis: emerging architectures, mechanistic insights, and future frontiers

Graphene-based nanocomposites have emerged as powerful photocatalysts because graphene’s unique 2D structure and chemistry dramatically improve light-driven reactions. In photocatalytic composites, graphene or its derivatives including graphene oxide (GO), reduced graphene oxide (rGO), and 3D graphene aerogels, serve as high-surface-area conductive scaffolds that promote charge separation, extend light absorption, and adsorb pollutants. As a result, graphene-supported catalysts exhibit greatly enhanced performance in environmental remediation (wastewater treatment and air purification), solar hydrogen evolution, and CO₂ photoreduction. This review surveys recent (2020–2025) advances in synthesis of graphene–semiconductor photocatalysts and elucidates the mechanisms by which graphene boosts activity. We discuss integration of graphene with common semiconductors (TiO₂, ZnO, and BiVO₄) and highlight representative applications in water purification, H₂ generation, and CO₂ conversion. Comparisons with other nanocomposite systems and key challenges (scalability, stability, and cost) are also addressed, drawing on findings from recent high-impact studies.