Nitrogen-rich graphitic carbon nitride (C3N5) as a sensing material for acetone detection

abstract

In this research, C3N5 materials were synthesized via thermal polycondensation of 3-amino-1,2,4-triazole at 450, 500, and 550 °C, and their performance as chemiresistive sensors for acetone vapor was evaluated at 300 °C. Gas sensing measurements were conducted across concentrations from 60 to 300 sccm. The sample synthesized at 550 °C exhibits the highest sensitivity, with a maximum response of 98 % at 300 sccm, followed by the 450 and 500 °C samples, which show responses of 36 % and 19 %, respectively. Despite its lower sensitivity, the 500 °C sample demonstrates the fastest response and recovery behavior, while the 550 °C sample shows slower kinetics, indicating a trade-off between structural ordering and adsorption capacity. Nitrogen adsorption-desorption analysis confirms a temperature-dependent increase in surface area (2.15 to 31.6 m2/g) and pore size (9.2 to 15.6 nm), enhancing gas accessibility. XRD analysis reveals interlayer expansion and partial graphitization in the 550 °C sample, while SEM shows laminated morphology favorable for acetone diffusion. UV¿Vis and FTIR spectra indicate redshifted absorption edges and the formation of ¿-conjugated, triazole-rich frameworks with increasing temperature. These structural and electronic features correlate with the observed sensing performance, demonstrating that thermal modulation of C3N5 enables control over porosity, molecular ordering, and charge transport for effective volatile organic compound detection. © 2025 Elsevier B.V.