Analysis of Ag-DP25/PET plasmonic nano-composites as a visible-light photocatalyst for wastewater treatment: Experimental/theoretical studies, and the DFT-MB degradation mechanism.

The development of polymeric-composites Agx%DP25-PET (x = 0,1,2,3) may significantly boost the potential application of Agx%DP25 (x = 0,1,2,3) photocatalytic powders. Producing large-scale nano-composites with hybrid-surfaces, that are also flexible materials and easy to employ in a variety of environments. A set of photocatalytic nan-composites embedded with the polymeric binder poly (acrylonitrile-co-butadiene)-dicarboxy terminated (C7H9N) were performed and evaluated for wastewater treatment applications. The results reveal that the flexible polymeric composites (Agx%DP25-PET, x = 0,1,2,3) have photocatalytic activity in aqua media to degrade methylene blue (MB) under visible-light. The addition of C7H9N to immobilize photocatalytic powders on the PET surface reduces photo-generated electron-hole recombination. The materials were characterized by HR-TEM, SEM/EDX, XRD, FT-IR, UV-Vis DRS and PL. The Agx%DP25-PET (x = 0,1,2,3) photocatalytic reactions exhibited productive discoloration/degradation rates, in both aerobic (AE) and anaerobic (AN) environments. The superior photodegradation of Ag2%DP25-PET was attributed to a combination of two effects: LSPR (localized surface plasmon resonance) and Ag-TiO2/environment affinities. The findings of molecular dynamics (MD) simulation and Fukui Function (FF) based on density functional theory (DFT) provide significant insight into the photocatalytic requirements for MB discoloration/degradation. The experimental/theoretical analysis aimed to offer an in-depth understanding of medium/surface interactions on decorated TiO2 materials, as well as how these interactions affect overall degradation behavior.

Dye-Sensitized Nanostructured Crystalline Mesoporous Tin-doped Indium Oxide Films with Tunable Thickness for Photoelectrochemical Applications.

A simple route towards nanostructured mesoporous Indium-Tin Oxide (templated nano-ITO) electrodes exhibiting both high conductivities and optimized bicontinuous pore-solid network is reported. The ITO films are first produced as an X-ray-amorphous, high surface area material, by adapting recently established template-directed sol-gel methods using Sn(IV) and In(III) salts. Carefully controlled temperature/atmosphere treatments convert the as-synthesized ITO films into nano-crystalline coatings with the cubic bixbyite structure. Specially, a multi-layered synthesis was successfully undertaken for tuning the film thickness. In order to evaluate the performances of templated nano-ITO as an electrode substrate for photoelectrochemical applications, photoelectrodes were prepared by covalent grafting of a redox-active dye, the complex [Ru(bpy)2(4,4'-(CH2PO3H2)2-bpy)]Cl21 (bpy=bipyridine). Surface coverage was shown to increase with the film thickness, from 0.7 × 10-9 mol.cm-2 (one layer, 45 nm) to 3.5 × 10-9 mol.cm-2 (ten layers, 470 nm), the latter value being ~ 100 times larger than that for commercially available planar ITO. In the presence of an electron mediator, photocurrents up to 50 µA.cm-2 have been measured under visible light irradiation, demonstrating the potential of this new templated nano-ITO preparation for the construction of efficient photoelectrochemical devices.