DOI: https://doi.org/10.55373/mjchem.v26i4.88

Keywords: Photoelectrochemical; photocatalysis; immobilization titanium dioxide; silver; RR4 dye

Abstract

In this study, a commercially available Degussa P25 TiO2 was used as a photocatalyst after a modification with silver (Ag) as a dopant to enhance the photocatalytic performance. This is due to the better migration of the generated electrons into the TiO2 when exposed to light. The preparation of Ag-TiO2 was conducted via the photo-deposition method, with silver nitrate (AgNO3) mixed with isopropyl alcohol (IPA) and distilled water (DW) as Ag precursor at various ratios of Ag dopant to TiO2. The immobilization of Ag-TiO2 was prepared via polymer-based immobilization by using epoxy natural rubber-50 (ENR50) and polyvinyl chloride (PVC) and the obtained photocatalyst was characterized by FESEM-EDS, XRD, 3D Profiler, FTIR and EIS. Photoelectrochemical degradation (PEC) was applied for photocatalytic performance measurement by using reactive red 4 (RR4) dye. The optimum photocatalytic performance of immobilized Ag-TiO2 was obtained at 24 V, labelled as (APV24), with almost complete degradation of 30 ppm RR4 dye achieved below 10 min under 55 W fluorescent lamp irradiation, which is faster compared to immobilized unmodified TiO2. The acquired results from FESEM-EDX and XRD analyses indicated the presence of Ag on Ag-TiO2 with no phase transformation. Based on conductivity study, a significant electron supply was observed on APV24 during the photocatalytic activity tended to generate hydroperoxyl and hydroxyl radicals, contributing to the degradation of the dye and floc formation throughout the process. The APV24 sample had shown the same photocatalytic degradation rate under immobilization due to the polymer-based formulation in the post-preparation of immobilization that was able to retain the photocatalytic activity.