Atomically
2D thin-layered structures, such as graphene nanosheets,
graphitic carbon nitride nanosheets (g-C3N4),
hexagonal boron nitride, and transition metal dichalcogenides are
emerging as fascinating materials for a good array of domains owing
to their rare physicochemical characteristics. In particular, graphitic
carbon nitride has turned into a hot subject in the scientific community
due to numerous qualities such as simple preparation, electrochemical
properties, high adsorption capacity, good photochemical properties,
thermal stability, and acid-alkali chemical resistance, etc. Basically, g-C3N4 is considered as a polymeric
material consisting of N and C atoms forming a tri-s-triazine network
connected by planar amino groups. In comparison with most C-based
materials, g-C3N4 possesses electron-rich characteristics,
basic moieties, and hydrogen-bonding groups owing to the presence
of hydrogen and nitrogen atoms; therefore, it is taken into account
as an interesting nominee to further complement carbon in applications
of functional materials. Nevertheless, g-C3N4 has some intrinsic limitations and drawbacks mainly related to a
relatively poor specific surface area, rapid charge recombination,
a limited light absorption range, and a poor dispersibility in both
aqueous and organic mediums. To overcome these shortcomings, numerous
chemical modification approaches have been conducted with the aim
of expanding the range of application of g-C3N4 and enhancing its properties. In the current review, the comprehensive
survey is conducted on g-C3N4 chemical functionalization
strategies including covalent and noncovalent approaches. Covalent
approaches consist of establishing covalent linkage between the g-C3N4 structure and the chemical modifier such as
oxidation/carboxylation, amidation, polymer grafting, etc., whereas the noncovalent approaches mainly consist of physical bonding
and intermolecular interaction such as van der Waals interactions,
electrostatic interactions, π–π interactions, and
so on. Furthermore, the preparation, characterization, and diverse
applications of functionalized g-C3N4 in various
domains are described and recapped. We believe that this work will
inspire scientists and readers to conduct research with the aim of
exploring other functionalization strategies for this material in
numerous applications.
