The coupled AgI/BiOI catalyst: Synthesis, brief characterization, and study of the kinetic of the EBT photodegradation

Abstract

The relatively novel AgI/BiOI coupled system (CS) was prepared in-situ by mechanical mixing of the as-synthesized AgI and BiOI nanoparticles (NPs) and characterized by various characterization techniques such as XRD, SEM-EDX, and UV–Vis DRS. XRD results showed the hexagonal crystals of AgI and the tetragonal crystals of BiOI in the CS. The grain sizes of 34.1 and 25.6 nm were estimated for the CS by the Scherrer and Williamson-Hall equations, respectively. The bandgap values of 2.7, 1.75, and 1.83 were estimated based on absorption edge wavelengths for AgI, BiOI, and CS samples, respectively. The CS showed a boosted photocatalytic activity towards Eriochrome Black T (EBT). This boosted activity depends on the amounts of the CS-ingredients and the CS with an AgI:BiOI mole ratio of 1:2 showed the highest activity. The photodegradation rate constant of 0.0167 min−1 with a t1/2 value of 41.5 min was obtained from the Hinshelwood plot. Further, the mineralization rate constant of 0.0137 min−1 with a t1/2 value of 50.6 min was obtained by applying the COD results in the Hinshelwood model.