A review on g-C3N4 and ZnO-modified g-C3N4 catalysts under visible irradiation: Precursor effects on properties and applications in sustainable developments

The current situation the world is facing is environmental pollution and energy shortage, which directly endangers the biosphere. Thus, a sustainable solution must be concluded to redeem the harsh conditions. Graphitic carbon nitride is an organic semiconductor that has caught the attention of scientists for facile synthesis and has been universally accessible. Accordingly, the material is reported to be synthesized from major nitrogen-containing precursors, along with the consideration of foreign elements. The advantages and disadvantages will be discussed to illuminate the suitable precursor choice or combination for the synthesis. Furthermore, several modification methods of graphitic carbon nitride will be introduced, including defect-inducing and heterojunction construction in order to overcome the drawback of the material. The decorating of zinc oxide, an inexpensive and non-toxic UV-driven photocatalyst can amplify the overall property and performance of the composite. Specifically, the synergetic effects of each component decorated onto the other are examined to overcome the disadvantages of each material. Therefore, the recolonized zinc oxide on graphitic carbon nitride can expand the application of the material in pollutant degradation like organic dyes and persistent organic compounds. Cleaner production of energy could also be achieved through H2 production and solar power harvesting, which also utilize the material as a catalyst and generator.