Efficient photocatalytic degradation of textile dye pollutants using thermally exfoliated graphitic carbon nitride (TE–g–C3N4)

Abstract Graphitic carbon nitride (g-C3N4), an organic semiconductor-based photocatalyst was reported to have several beneficial properties to be used in wastewater treatment applications. However, g-C3N4, in its bulk form has poor photocatalytic degradation efficiency due to its inherent limitations such as poor specific surface area and fast electron-hole pair recombination rate. In this study, we have tuned the physiochemical properties of bulk g-C3N4 by direct thermal exfoliation and examined their photocatalytic degradation efficiency against abundant textile dyes such as methylene blue (MB), methyl orange (MO), and rhodamine B (RhB). The degradation efficiencies for MB, MO, and RhB dyes are 92 ± 0.18%, 93 ± 0.31%, and 95 ± 0.4% respectively in 60 min of UV light irradiation. The degradation efficiency increases with an increase in the exfoliation temperature. The prepared catalysts were characterized using FTIR, XRD, FE-SEM, EDAX, BET, and UV-DRS, to confirm their material structure, phase, surface morphology, elemental composition, specific surface area and optical properties respectively. Further, adsorption efficiency and reusability were also tested. The findings derived from the scavenging studies revealed that the involvement of superoxide radicals was the most crucial in the process of photodegradation for all dyes. PL emission and EIS spectra of exfoliated g-C3N4 indicated a decrease in the recombination rate of electron-hole pairs created by photoexcitation and enhancement in the efficiency of photo-induced charge transfer. Further, the exfoliated g-C3N4 photocatalysts were found to have excellent stability for up to 5 cycles with a minor decrease in the activity. These findings proved that exfoliated g-C3N4can be an excellent photocatalyst for the removal and degradation of textile dyes from wastewater.