Graphitic carbon nitride: Synthesis, characterization and photocatalytic decomposition of nitrous oxide

Abstract

Graphitic carbon nitride (g-C3N4) was synthetized by condensation of melamine at the temperatures of 400-700 degrees C in air for 2 h and resulting products were characterized and finally tested for the photocatalytic decomposition of nitrous oxide.

The characterization methods were elemental analysis, UV-Vis diffuse reflectance spectroscopy (DRS), photoluminescence (PL), Fourier transform infrared (FTIR) and Raman spectroscopy, measurement of specific surface area (SSA), X-ray powder diffraction (XRD), scanning (SEM) and transmission (TEM) electron microscopy. The XRD patterns, FTIR and Raman spectra proved the presence of g-C3N4 at above 550 degrees C but the optimal synthesis temperature of 600-650 degrees C was found. Under these conditions graphitic carbon nitride of the overall empirical composition of C6N9H2 was formed. At lower temperatures g-C3N4 with a higher content of hydrogen was formed but at higher temperatures g-C3N4 was decomposed. At the temperatures above 650 degrees C, its exfoliation was observed.

The photocatalytic experiments showed that the activity of all the samples synthetized at 400-700 degrees C was very similar, that is, within the range of experimental error (5 %). The total conversion of N2O reached about 43 % after 14 h.