Issue 3, 2023

A mechanistic study of the photocatalytic activity of AgI–WO3 in an experimentally designed approach toward methylene blue photodegradation

Abstract

The visible light–active AgI/WO3 binary photocatalyst has been characterized using XRD, FTIR spectroscopy, SEM-EDX, cyclic voltammetry (CV), photoluminescence (PL), and UV–vis DRS techniques. An average crystallite size of 37.7 nm was obtained for AgI/WO3, including the hexagonal wurtzite β-AgI and monoclinic WO3 crystallites. Band gap energies of 2.27, 2.87, and 2.52 eV were obtained for AgI, WO3, and AgI/WO3 samples, and the potential positions of the valence and conduction bands were also estimated. The superior photodegradation activity of AgI/WO3 concerning the individual system was confirmed, with a methylene blue (MB) degradation efficiency of 95% in a 5 ppm MB solution. The optimal RSM run with the best response occurred with pH 6.63, catalyst dosage of 1.12 g L−1, irradiation time of 47 min, and CMB of 3.26 ppm. Further, the RSM central point run conditions were pH 6.1, catalyst dosage of 1.05 g L−1, irradiation time of 35 min, and CMB of 5.5 ppm. Radical trapping experiments using scavenging agents revealed that hydroxyl radicals (˙OH) and holes (h+) were the predominant reactive species during MB photodegradation using the AgI/WO3 system. The direct Z-scheme mechanism was the best photocatalytic system to describe MB photodegradation based on the results and potential positions of the VB and CB of the semiconductors.

Graphical abstract: A mechanistic study of the photocatalytic activity of AgI–WO3 in an experimentally designed approach toward methylene blue photodegradation

Supplementary files

Article information

Article type
Paper
Submitted
19 Oct 2022
Accepted
29 Nov 2022
First published
14 Dec 2022

Catal. Sci. Technol., 2023,13, 737-749

A mechanistic study of the photocatalytic activity of AgI–WO3 in an experimentally designed approach toward methylene blue photodegradation

S. Ghattavi and A. Nezamzadeh-Ejhieh, Catal. Sci. Technol., 2023, 13, 737 DOI: 10.1039/D2CY01815B

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