Synergistic photocatalytic reduction of chemical oxygen demand in acetophenone-containing wastewater using a hybrid LaMnCeO3/TiO2–MXene/Al-HMS nanocomposite under visible irradiation

A novel quaternary hybrid photocatalyst, LaMnCeO 3 /TiO 2 –MXene/Al-HMS, was successfully synthesized and applied for the visible-light-driven degradation of acetophenone in aqueous solution. Structural and morphological characterization (XRD, FTIR, TEM, FESEM, BET, and XPS) confirmed the uniform integration of LaMnCeO 3 , TiO 2 , MXene, and mesoporous Al-HMS, forming a hierarchical architecture with high surface area and enhanced interfacial interactions. Photocatalytic studies demonstrated that the quaternary catalyst exhibited superior performance compared to its binary and individual components, achieving up to 88.12% chemical oxygen demand reduction at pH 3, 5 ppm acetophenone, and 90 min irradiation. The chemical oxygen demand was strongly influenced by solution pH, initial pollutant concentration, and irradiation time, with acidic conditions and low acetophenone loading favoring improved adsorption and reactive oxygen species generation. Scavenger experiments revealed that photogenerated holes (h + ) were the primary reactive species, with superoxide radicals ( · O 2 − ) contributing partially and hydroxyl radicals ( · OH) playing a minor role. The enhanced activity was attributed to the synergistic effects of visible-light absorption by LaMnCeO 3 , rapid electron transfer via MXene, and adsorption-assisted concentration of acetophenone molecules by Al-HMS. The catalyst also exhibited excellent stability and reusability, retaining over 81% activity after five consecutive cycles, demonstrating its potential for the treatment of industrial wastewater containing recalcitrant organic pollutants.