Recent progress in the preparation and application of semiconductor/graphene composite photocatalysts

Graphene is a new material with a single-layer laminar structure of carbon atoms that possesses favorable physical and chemical properties such as high electrical conductivity, high chemical stability, and large specific surface area. Combining graphene with semiconductors to form composite photocatalysts can extend its light absorption edge, improve the migration rate of charge carriers, and enhance the adsorption capacity of contaminants. The unique two-dimensional planar structure of graphene endows composite photocatalysts with many excellent properties. Herein, the properties of graphene, semiconductor, and composite photocatalysts are first introduced. The various preparation methods of semiconductor/graphene composite photocatalysts are then presented, and the mechanisms behind enhanced photocatalysis are summarized. Four typical applications of composite photocatalysts: elimination of organic pollutants, hydrogen production, organic fuel production via CO₂ reduction, and photocatalytic sterilization, are described in detail. Finally, the direction of future research on semiconductor/graphene composite photocatalysts is explored.