The Role of Aluminum in Graphitic Carbon Nitride Synthesis from Tiourea

Abstract

The synthesis of a composite material based on graphitic carbon nitride by pyrolytic decomposition at 550 °C of a mechanical mixture of thiourea with the addition of aluminum powder in the amount of 5–30 wt.% has been studied. According to the scanning results by means of electron microscopy, energy dispersive X-ray spectroscopy, and X-ray diffractometry the synthesized material consists of carbon nitride, aluminum sulfide, residual metallic aluminum and aluminum hydroxide. The excess of metallic aluminum is due to the partial interaction with sulfur-containing volatile substances formed during the thermal decomposition of thiourea. It is shown that the intensity and width of the photoluminescence spectra of the synthesized composites are determined by the aluminum concentration in the initial mixture. As the aluminum concentration increases from 5 to 30 wt.%, the photoluminescence intensity maximum shifts to the long wavelength region from 534 to 560 nm. This can be used to create optoelectronic devices based on the graphitic carbon nitride.