Anthology on graphitic carbon nitride (g-C3N5) coping experimental synthesis, theoretical studies, characterization, and its deployment in biological, environmental, energy conversion and storage

Abstract

Unique optical and electronic characteristics of g-C3N5 paved for its own spectra in recent research. The high-nitrogen content and narrowed band gap than g-C3N4 had made g-C3N5 an explicit nitrogen-rich semiconducting material. The optical absorption characteristic is an implicit function of the number of stacking layers resulting in a tunable bandgap with an added advantage of light-harnessing ability in the visible region. In this review, we covered all the aspects starting from three stable g-C3N5 molecular structures, and various preparation of g-C3N5 using template and template-free methods from various precursors and their characterization techniques. Besides, this review exemplified its excellent characteristics, counting from their heterojunction formation, electronic, electrochemical, physicochemical, optical, and photoelectrochemical properties. In addition, g-C3N5 can improve its charge separation ability by forming a Schottky junction while tailoring with a metal dopant. The inherent visible light harnessing and charge carrier separation ability of g-C3N5 made this material (in composite with other materials) a photocatalyst in various fields including pollutant degradation, hydrogen generation, NOx removal, and CO2 adsorption. The theoretical calculations, and the DFT outcome supports the charge separation ability of C3N5, which was witnessed from the spatial distribution of charges in HOMO-LUMO. It further supports that layered ultrathin C3N5 had a longer photogenerated electrons lifetime than the bulk one with higher negative conduction band potential. In concluding note, future perspectives of g-C3N5 and suggestions were proposed on making composite material with the aforementioned.