Facile synthesis and comparative study of the enhanced photocatalytic degradation of two selected dyes by TiO₂-g-C₃N₄ composite

Photocatalysis is considered a useful technique employed for the dye degradation through solar light, visible or UV light irradiation. In this study, TiO₂, g-C₃N₄, and TiO₂-g-C₃N₄ nanocomposites were successfully synthesized and studied for their ability to degrade Rhodamine B (RhB) and Reactive Orange 16 (RO-16), when exposed to visible light. The analytical techniques including XRD, TEM, SEM, DRS, BET, XPS, and fluorescence spectroscopy were used to explore the characteristics of all the prepared semiconductors. The photocatalytic performance of synthesized materials has been tested against both the selected dyes, and various experimental parameters were studied. The experimental results demonstrate that, in comparison to other fabricated composites, the TiO₂-g-C₃N₄ composite with the optimal weight ratio of g-C₃N₄ (15 wt%) to TiO₂ has shown outstanding degrading efficiency against RhB (89.62%) and RO-16 (97.20%). The degradation experiments were carried out at optimal conditions such as a catalyst load of 0.07 g, a dye concentration of 50 ppm, and a temperature of 50 ℃ at neutral pH in 90 min. In comparison to pure TiO₂ and g-C₃N₄, the TiO₂-g-C₃N₄, a semiconductor, has shown higher degradation efficiency due to its large surface area and decreased electron–hole recombination. The scavenger study gave an idea about the primary active species (⁻OH radicals), responsible for dye degradation. The reusability of TiO₂-g-C₃N₄ was also examined in order to assess the composite sustainability.