Tailoring energy band gap and microwave absorbing features of graphite-like carbon nitride (g-C3N4)

Currently, two-dimensional (2D) nanostructures have attracted considerable attentions originated from their salient features. Accordingly, the widespread methods have been used to improve their abilities. In this study, g-C3N4 2D structure was synthesized using a conventional route and its structure was distorted by inserting and exhausting citric acid as a novel defecting precursor by sonochemistry, hydrothermal, and combustion methods as an innovative complementary process. Noteworthy, g-C3N4 aerogel (GA) was obtained by tuning the loading mass fraction of melamine to volume of the alumina crucible. The architected materials were characterized using diffuse reflection spectroscopy (DRS), field emission scanning electron microscopy (FE-SEM), X-ray powder diffraction (XRD), thermogravimetric analysis (TGA), Fourier transform infrared (FTIR), and vector network analyzer (VNA). Furthermore, the surface characteristics of the tailored structures were evaluated by N-2 adsorption-desorption isotherms. The analyses attested that the pure crystal and chemical structures of g-C3N4 have been produced while the presented route has enhanced crystallinity and developed defects into the nanosheets. The crystal distortions of 2D structures led to the remarkable optical and microwave absorbing features. Besides, polyacrylonitrile (PAN) was applied as an absorbing medium to prepare microwave absorbers. Interestingly, GA brought a significant reflection loss (RL) of 74.92 dB at 11.85 GHz, whereas defected g-C3N4/PAN 30% illustrated broadband efficient bandwidth as wide as 3.56 GHz with a RL > 20 dB. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

This study focuses on synthesizing g-C3N4 2D structures using innovative methods, and characterizing their properties through various experiments. The research demonstrates that the tailored 2D nanostructures exhibit excellent optical and microwave absorbing features.