Experimental and density functional theory study on the efficient degradation of methyl orange dye by Ag2O/TiO2 composite photocatalyst driven by low-power irradiation

BACKGROUND

The invention of a highly efficient photocatalyst is of profound significance for degradation of organic species in wastewater. Here, Ag₂O/TiO₂ composite photocatalyst was synthesized by metal deposition method. The structure and property of the as-prepared photocatalyst was characterized by scanning electron microscopy, X-ray photoelectron spectroscopy, Fourier-transform infrared spectroscopy, X-ray diffraction, Mott–Schottky measurements and ultraviolet–visible spectrophotometry.

RESULTS

The effects of the constituent proportion of photocatalyst, pH value of solution, initial concentration and catalyst dosage on the photocatalytic degradation of methyl orange (MO) were investigated under 36 W low-power light irradiation. The degradation mechanism was revealed by scavenger test and density functional theory calculation. In addition, the cycle life of the photocatalyst was further examined. The photocatalytic decolorization degree of MO in water can reach up to 99.99% under the optimal conditions of photocatalyst usage of 0.2 g, constituent proportion of 0.5:10, initial MO concentration of 5 mg L⁻¹ and pH of 4. At the same time, the reaction rate coefficient of Langmuir–Hinshelwood is regressed as 0.05973 min⁻¹.

CONCLUSION

The photocatalyst presents a superior photocatalytic oxidation performance with the degradation degree remaining up to 99.8% for MO even after recycling three times. © 2025 Society of Chemical Industry (SCI).