S-scheme MgO–TiO₂@g-C₃N₄ nanostructures as efficient photocatalyst for alizarin red S photodegradation

In this study a ternary composite MgO–TiO₂@g-C₃N₄ was synthesized via a simplistic ultrasonic route and then it was characterized using various techniques. The development of tri-phased nanostructure was revealed by the X-ray diffraction (XRD) analysis. The X-ray photoelectron spectra (XPS) study confirmed the presence of the constituent elements while the bonding patterns were investigated by the Fourier transform infrared (FTIR). The as-acquired MgO–TiO₂@g-C₃N₄ heterojunction exhibited an optimal competence (94%) and enhanced photo-degradation rate constant towards the Alizarin Red S (ARS) dye in just 60 min under visible-light illumination. The heterostructured combined interfaces assembly of g-C₃N₄ and MgO–TiO₂ NPs, have efficiently prompted the photo-excited charges separation, and blocked the recombination incidence. Henceforth, the prolonged lifetime has led to incessant generation of photoactive⁻ species that ultimately upgraded the photo-degradation process. Furthermore, the fabricated hybrid photocatalysts showed superior recycling stability. A plausible photocatalytic reaction mechanism based on the S-scheme has been proposed. The advanced photocatalytic competence to degrade the AR dye under visible light irradiation makes MgO–TiO₂@g-C₃N₄ a favorable photocatalyst for the dye-containing wastewater treatment.