Photoenhanced Degradation of Methylene Blue on Cosputtered M:TiO₂ (M = Au, Ag, Cu) Nanocomposite Systems: A Comparative Study

Abstract

Titania thin film system containing noble metallic nanoparticles such as Au, Ag, and Cu have been prepared by utilizing radio frequency reactive magnetron cosputtering method. The structural and morphological properties of the thin films were characterized by X-ray diffraction (XRD) and atomic force microscopy (AFM). Surface chemical composition of the films was determined by X-ray photoelectron spectroscopy (XPS). Optical properties of the TiO2 annealed films containing Au, Ag, and Cu metallic nanoparticles were investigated by UV−visible spectrophotometry showing surface plasmon resonance of the metals. The photocatalytic activity of all synthesized samples annealed at 600 °C in an Ar + H2(80 + 20%) environment was evaluated by measuring the rate of photodegradation reaction of methylene blue (MB) under similar conditions in the presence of UV and visible light irradiation. The Au:TiO2 and Cu:TiO2 thin film systems significantly enhanced photodecomposition of MB resulting in 80 and 90% of its initial concentration after 200 min photoirradiation, respectively. The increase in the surface roughness measured by AFM observation and the presence of the Ti3+ oxygen vacancy in the photoirradiated thin films were found responsible for the enhancement of the MB photodegradation reaction. The photoenhancement of the studied was determined in the following order: Cu:TiO2 > Au:TiO2 > Ag:TiO2 > TiO2.

Synthesis of doubly functional nanowhiskers from a colloid solution including a V–Ti complex precursor

“…0.0013 and 0.0017, respectively. The result agrees with previous findings for other systems [20]. Although the content of TiO 2 in the Ti/V oxide nanowhiskers was only approximately 0.36 %, these two values of k are similar.…”

“…Figure 5a presents the SEM image of the precursor of the V/Ti complex that had been prepared solely in an aqueous 20 solution. The product of the V/Ti precursor had an amorphous structure of irregular particles having dimensions of less than 3 9 10 lm (mainly ca.…”

Fabrication of polythiophene–TiO2 heterojunction solar cells coupled with upconversion nanoparticles

“…It is reported that in aqueous systems, the photoexcited TiO 2 can abstract hydrogen from H 2 O, which contributes to generate the majority of the ÁOH [25][26][27]. As indicated by the relevant research, ÁOH can be captured by coumarin to produce the fluorescent 7-hydroxycoumarin, which has the characteristic emission peak at the wavelength of 456 nm [25].…”

Hydrogen Photoproduction from Ethanol–Water Mixtures Over Au–Cu Alloy Nanoparticles Supported on TiO2

“…The drawback, however, is the high costs incurred by the use of noble metals. For this reason, increasing attention has been devoted to Cu/Cu 2 O/CuO nanoparticles dispersed on TiO 2 [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25] to attain a cost-effective photocatalyst. Copper species with smaller bandgap and higher work function than bare TiO 2 facilitates light harvesting and charge carrier separation in Cu/TiO 2 .…”