Developing the Ag-Decorated TiO2-SiO2/SiO2 Multilayer Thin Films on Honeycomb Monolith Reactors for Regulating the Photocatalytic Removal of Organic Contaminants in Aqueous Media

TiO2-based thin-film films are considered a potential photocatalyst for the removal of dangerous contaminants from wastewater. In this work, a dipcoating approach was used to create TiO2-SiO2 thin layer onto multichannels of cordierite honeycomb monolith (CHM). Adding SiO2 washcoat between the TiO2-SiO2 layer and the substrate was to increase the stability and catalytic surface area. Silver nanoparticles were applied using the photodeposition technique to the TiO2-SiO2/SiO2/CHM system. Using XRD, UV-Vis DRS, XPS, BET, PL, FE-SEM, and GC-MS, the catalysts were characterized. The prepared materials’ photocatalytic activity was assessed by degrading 10 mg L−1 2-naphthol solution (2NAP) in the presence of LED UV light irradiation. The maximum photoactivity was obtained in the 5 wt% Ag-decorated TiO2-SiO2/SiO2/CHM (5A-TS5/2S/2S600/M) sample, which eliminated 93.54% of the 2NAP after 90 min of irradiation, compared to 80.36% 2NAP degradation achieved by the sample without Ag (TS5/2S/2S600/M). After five runs, the 5A-TS/S/S600/M showed its stability and reusability with a marginally reduced yield of 6.22% and a meager 1.42 wt% loss.