From lab to environment: a critical eye approach toward morphological synthesis of graphitic carbon nitride for environmental restoration

Urbanization, industrialization, population growth, and resource exploitation are causing global freshwater scarcity and environmental deterioration due to industrial effluents and emissions. This results in the presence of dangerous substances and toxic pollutants, which raises significant worldwide concerns. Considering the increasing environmental issues, it is essential to develop innovative and durable strategies for mitigating pollution. Graphitic carbon nitride (GCN or g-C₃N₄), a metal-free photocatalyst, has demonstrated potential as a material for environmental remediation. This is attributed to its distinctive physicochemical properties, electronic band structure, non-toxic nature, abundance of raw materials, simple preparation methods, and ability to utilize solar energy. However, the limited ability of pure g-C₃N₄ to undergo reduction and oxidation, as well as its high rate of recombination of photogenerated electron–hole pairs, restricts its applicability in photocatalysis. These issues have been overcome through the implementation of several modifications, including elemental doping, heterojunction building, morphological adjustments, and defect engineering. This review article provides a thorough overview of photocatalysts based on g-C₃N₄ that are utilized for the elimination of various types of pollutants, including both organic and inorganic contaminants.