DOI: https://doi.org/10.55373/mjchem.v25i4.184

Keywords: Immobilized TiO2; reversed photodeposition; DSAT immobilization; photocatalytic degradation; silver oxide

Abstract

A new immobilized Z-scheme heterojunction of Ag2O/Ag doped TiO2 using a reverse technique to prevent excess chemical usage was prepared by immobilizing TiO2 prior to doping with silver and silver oxide nanoparticles by a photodeposition method using a 250-Watt fluorescent lamp irradiation process for 60 min. TiO2 was coated onto double-sided adhesive tape (DSAT) using the brush technique, and a glass plate measuring 10 x 1.5 x 0.2 cm (L x H x B) was used as the support material for immobilization. Reactive Red 4 (RR4) dye was used as a model pollutant to measure the photocatalytic activity of the prepared immobilized Ag2O/Ag-TiO2. Characterization was performed by X-ray diffraction, photoluminescence, UV-vis diffuse reflectance spectroscopy and FESEM equipped with energy dispersive X-ray analysis (EDX). The results showed that Z-scheme heterojunctions of Ag2O/Ag-TiO2 significantly enhanced photocatalytic degradation compared to the N-type TiO2 microsphere. In comparison with pure TiO2, the modified composite photocatalyst exhibited higher photocatalytic activity under visible light irradiation in the decomposition of RR4 in aqueous solution. The photocatalytic degradation followed the pseudo-first-order reaction model. The heterostructure with a 3 % molar ratio of TiO2 and AgNO3 exhibited the best photocatalytic activity with an apparent first-order rate constant of 0.321 min–1.