Polymeric organic-inorganic C3N4/ZnO high-performance material for visible light photodegradation of organic pollutants

Photocatalysis is a clean, cost-effective and time-efficient method for degradation of organic pollutants and also other usages such as CO2 photoreduction. In this field, the development of suitable photocatalysts that can be active under visible light irradiation has received much attention and research. To achieve this goal, making photocatalysts with a suitable bandgap can be effective. By combining several suitable materials and making nanocomposites, this goal can be achieved. However, the synthesis method, particle size, surface area and crystallinity can be effective on the photocatalytic properties of the nanocomposites. C3N4 is a low-cost material with good photoactivity properties. Also, this material is thermally and chemically stable. Zinc oxide also is a non-toxic, cost-effective and available photocatalyst. But some limitations such as wide band gap led to decreasing the visible light photoactivity of zinc oxide and also carbon nitride materials. Coupling an organic material like C3N4 with inorganic zinc oxide causes a heterojunction material with interesting properties in degradation of various organic pollutants such as in pesticides and organic dyes. This review accounts with ZnO-doped C3N4 heterostructure and advance methods of construction, photocatalytic efficiency, recycling stability and the mechanism of photodegradation. The photoactivity of ZnO-C3N4 nanocomposite is higher than ZnO and C3N4 nanomaterials. Moreover, modification of the ZnO-C3N4 nanocomposite with doping other metals such as Al, Mg, Ni, Cu, Ag significantly improves the photoactivity. The mechanism of photodegradation of this nanocomposite can be based on photo-oxidation and also photoreduction mechanism. Based on photoreduction mechanism this nanocomposite can be applied to CO2 photoreduction.