Metal-free hybrid nanocomposites of graphitic carbon nitride and char: Synthesis, characterisation and photocatalysis under visible irradiation

Abstract

Background The hybrid nanocomposites of graphitic carbon nitride (g-C3N4) and char were synthesised from melamine and hydroxyethyl cellulose/glucose to obtain metal-free photocatalysts active under visible irradiation. The nanocomposites were tested for the degradation of phenol and ofloxacin. Methods The nanocomposites were characterized by elemental and thermal analysis. Their electronic properties were studied by UV–Vis and photoluminescence spectroscopy. Texture and morphology were studied by physisorption of nitrogen, X-ray diffraction, infrared spectroscopy, X-ray photoelectron spectroscopy, and by transmission electron microscopy. The photocatalytic experiments were performed under the LED irradiation of 420 nm. Significant findings Hydroxyethyl cellulose and glucose formed char which was incorporated in the g-C3N4 structure. The char acted as an electron collector enabling the separation of photoinduced electrons and holes. In this way, the photocatalytic activity of g-C3N4 increased and 96% of ofloxacin was degraded during after 120 min. In addition, in this work the total combustion of graphitic carbon nitride up to 800 oC was investigated for the first time.