The Role of Carbon-based Nanomaterials as Cocatalysts in Enhancing the Photocatalytic Hydrogen Production: A Review

Hydrogen is recognized as a potential clean energy carrierto replace fossil fuels due to its high energy density and improved combustiontemperature. Photocatalytic water splitting (PWS) systems using solar energyoffer potential solutions to both energy crises and environmental issues. Overrecent decades, solar-based catalysts have been developed and utilized toproduce sustainable and renewable fuels. Researchers are focused on designingcatalysts that are inexpensive, stable, and can efficiently capture light.Further, the advancement of effective catalysts for water redox reactions insuspension is essential for harnessing solar energy. However, the limitationsof the semiconductor catalysts still result in the reduction of catalyticefficiency for hydrogen evolution. Thus, carbon-based materials serve as promisingcatalysts for PWS owing to their physical and chemical properties. This reviewpresents an extensive overview of heterojunction systems and carbonnanomaterials, including graphene, carbon nanotubes, graphitic carbon nitride, etc as cocatalysts in enhancing the efficiency of semiconductor photocatalystsfor hydrogen evolution. This current review further addresses how factorssuch as heteroatom doping, defects, and dimensions can influence theperformance of photocatalytic carbon materials in hydrogen generation. Finally, the obstacles that hinder the progress of the PWS process as well asfuture prospects, are discussed.