International Research Journal of Basic and Clinical Studies Vol. 8(4) pp. 1-14, August, 2023 Available online http://www.interesjournals.org/IRJBCS Copyright ©2023 International Research Journals Graphitic Carbon Nitride Quantum Dots (g-C3N4): Fundamentals and Applications Loutfy H Madkour* Prof. Loutfy H. Madkour: Professor of Physical chemistry, Nanoscience and Nanotechnology Chemistry Department, Faculty of Science, Tanta University, 31527, Tanta, Egypt *Corresponding Author's E-mail: loutfy_madkour@yahoo.com, lha.madkour@gmail.com; Tel: +201026724286 (Egypt) Received: 01-Aug-2023, Manuscript No. irjbcs-23-107710; Editor assigned: 04-Aug-2023, PreQC No. irjbcs-23-107710 (PQ); Reviewed: 18-Aug-2023, QC No. irjbcs-23-107710; Revised: 25-Aug-2023, Manuscript No. irjbcs-23-107710 (R); Published: 31-Aug-2023, DOI: 10.14303/irjbcs.2023.48 Abstract As a novel C and N based two-dimensional material, graphitic carbon nitride quantum dots (g-C3N4) QDs is regarded as a new generation of photocatalyst and has been widely used in the feld of environmental photocatalysis. In recent years, graphitic carbon nitride has become one of the very exciting sustainable materials, due to its unusual properties and promising applications as a heterogeneous catalyst in water splitting and organic contaminant degradation. A variety of modifcations have been reported for this nanostructured material with the use of carbonaceous materials to enhance its potential applications. Carbon nitrides (C3N4) are renowned organic semiconductors with a band gap of 2.7 eV, which are connected via tri-s-triazine-based forms. Graphitic carbon nitride (g-C3N4) is considered as an attractive, efcient and newly generated promising visible light–driven photocatalyst ascribable material owing to its distinct properties such as metal free, suitable band gap, chemical inertness and high physicochemical stability. Nevertheless, the photocatalytic activity of pure g-C3N4 was limited by the fast recombination rate of photoinduced electron–hole pairs, poor photoexcited charge separation, limited range of visible light absorption and relatively low specifc surface area. Enhanced photocatalytic activity is achievable by the construction of homojunction nanocomposites to reduce the undesired recombination of photogenerated charge carriers. The formed g-C3N4 isotype heterojunction photocatalyst manifested signifcant improvement photocatalytic hydrogen production than the single and pure g-C3N4 sample. This signifcant enhanced photocatalytic performance is mainly ascribed to inhibited recombination, enriched active site and enlarged specifc surface area. Hence, current chapter on g-C3N4 mainly focuses on basics, properties, and fundamentals of its synthesis and its applications with an aim to improving its photocatalytic performance. In this chapter, the background of photocatalysis, mechanism of photocatalysis, and the several researches on the heterostructure graphitic carbon nitride (g-C3N4) semiconductor are discussed. This research gives a useful knowledge on the heterostructure g-C3N4 and their photocatalytic mechanisms and applications. Finally, the challenges and future research directions of g-C3N4 photocatalysts are summarized to promote their environmental applications. The advantages of the heterostructure g-C3N4 over their precursors are also discussed. The conclusion and future perspectives on this emerging research direction are given. Keywords: Graphitic carbon nitride (g-C3N4), Photocatalysis, Pollutant degradation, Semiconductors Review Article INTRODUCTION Carbon nitrides are compounds that contain carbon and nitrogen as major elements with the general chemical formula C 3 N 4 . In these compounds, carbon atoms are fourfold sp 3 bonded with nitrogen atoms in a regular tetrahedron and then it is connected by other nitrogen atoms having a planar structure, thereby forming a sp 2 bond (Gao et al., 2004). g-C 3 N 4 is a polymeric material composed of tris- triazine-based paterns with the C/N rato=3/4 and small