Next generation sustainable nano-carbon photocatalysts for environmental purification

The exceptional physicochemical properties of nano-carbon have gained attention as an auspicious material for a variety of practical applications. Recently, these materials were reported in many diverse areas like photocatalysis, electrocatalysis, energy storage, energy generation and conversion, gas sorption, adsorption, tribology, etc. Nano-carbon has unique intrinsic properties of large pore volume, size, unique pore size distribution, high specific surface area. Further, high electrical conductivity with a good number of active makes nano-carbon a potential candidate for photocatalysis. In photocatalysis, the band gap and activity in light are two important factors that make a material active or inactive for the reaction. The nano-carbon is a good photocatalyst as it can be used as such or with perturbation of its framework with metal, metal oxides, and heteroatoms, which further enhances the applications. The nano-carbon can be synthesized by different methods: chemical activation, hydrothermal/solvothermal process, microwave-assisted synthesis, carbonization, etc. of chemical precursors or abundant biomass available in nature. In this article, the methods, materials and mechanism for photodegradation have been discussed to treat toxic pollutants like dyes, chemicals, heavy metals, pharma waste, CO₂ reduction etc.