Synthesis and photocatalytic activity of BiOI particles: An efficient visible-light-driven degradation of organic pollutants in aqueous environments

Abstract

Bismuth oxyiodide (BiOI) particles were successfully fabricated through solvothermal activation using bismuth (III) nitrate pentahydrate and potassium iodide as precursors. The photocatalytic activities of BiOI were investigated under the influence of synthesis temperature (120–200 °C) with a fixed duration of 12 h. The physical-chemical properties of the samples were systematically investigated using X-ray diffraction, scanning electron microscopy, N₂-sorption isotherm techniques, and pH of the point of zero charge (pH_pzc). The prepared BiOI exhibited a single phase with a non-uniform 2D morphology with different sizes, an average crystallite size of 30 nm, and a BET surface area of 20.71 m²g⁻¹. The zero-point charge was determined to be 7.7. The photocatalytic performance under simulated solar light irradiation was investigated by examining the effects of dye initial concentration, catalyst dose, and dye pH. Remarkably, BiOI synthesized at 160 °C demonstrated an impressive 85% removal efficiency of 10 ppm MO (methyl orange) at normal pH levels (pH 6.8) within 120 min under visible light irradiation, along with the highest rate constant of 0.01418 min⁻¹. The quenching effects of different scavengers indicate the significant role of reactive O₂•– and a minor role of h_VB+ and •OH_ads in the photocatalytic process. These findings underscore the potential of BiOI particles as efficient photocatalysts for environmental applications, particularly in the degradation of organic pollutants in water using solar light irradiation.