The effect of nanoparticles size on photocatalytic and antimicrobial properties of Ag-Pt/TiO2 photocatalysts

Abstract

Please cite this article as: A. Zielińska-Jurek, Z. Wei, I. Wysocka, P. Szweda, E. Kowalska, The effect of nanoparticles size on photocatalytic and antimicrobial properties of Ag-Pt/TiO 2 photocatalysts, Applied Surface Science (2015), http://dx.A c c e p t e d M a n u s c r i p t Highlights  Enhanced photocatalytic activity under visible light for bimetallic Ag-Pt/TiO 2 was observed  Phenol was removed efficiently after 60 min. irradiation under Vis  Most active sample contains fine Pt (1-3nm) on TiO 2  Ag/TiO 2 , Ag-Pt/TiO 2 revealed antimicrobial activity AbstractAg-Pt -modified TiO 2 nanocomposites were synthesized using the sol-gel method.Bimetallic modified TiO 2 nanoparticles exhibited improved photocatalytic activity under visible-light irradiation, better than monometallic Ag/TiO 2 and Pt/TiO 2 nanoparticles (NPs). All modified powders showed localized surface plasmon resonance (LSPR) in visible region. The photocatalysts' characteristics by X-ray diffractometry (XRD), scanning transmission electron microscopy (STEM), diffuse reflectance spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS), nitrogen adsorption (BET method for specific surface area) showed that sample with the highest photocatalytic activity had anatase structure, about 93 m 2 /g specific surface area, maximum plasmon absorption at ca. 420 nm and contained small NPs of silver of 6 nm and very fine platinum NPs of 3 nm.The photocatalytic activity was estimated by measuring the decomposition rate of phenol in 0.2 mM aqueous solution under Vis and UV/Vis light irradiation. It was found that size of platinum was decisive for the photocatalytic activity under visible light irradiation, i.e., the smaller Pt NPs were, the higher was photocatalytic activity. While, antimicrobial activities, estimated for bacteria E. coli and St. aureus, and pathogenic fungi belonging to A c c e p t e d M a n u s c r i p t Candida family, were only observed for photocatalysts containing silver, i.e., Ag/TiO 2 and Ag-Pt/TiO 2 nanocomposites.

Mono- and Dual-modified Titania with a Ruthenium(II) Complex and Silver Nanoparticles for Photocatalytic Degradation of Organic Compounds

“…Moreover, the existence of particles would induce scattering effect which is observed in the DRS spectra. By applying bare titania as reference (Figure 4b), the plasmon bands with a maxima at around 400 nm was clear for single silver modified titania, which is comparable with the literature (20)(21). Therein, it was also proposed that the source of titania would shift the maxima plasmon bands for silver NPs.…”

“…Therefore, the presence of ruthenium(II) was confirmed in all Ru II CP2-contained samples, based on this absorption. For plasmonic metal nanoparticles, usually, broad absorption in the range of 400-800 nm is observed by their localized surface plasmon resonance, especially in the case of nanoparticles possessing broad distribution of sizes and shapes (21). Moreover, the existence of particles would induce scattering effect which is observed in the DRS spectra.…”

“…Silver as the metal deposit has the advantage of the lower cost and the stronger electron storage capacity when compared to gold (19), and its antimicrobiological properties as well (20,21). Besides, ruthenium(II) complexes, which exhibit the desirable visible absorption of metal to ligand charge transfer (MLCT), have also been widely applied to sensitize titania (22,23).…”

“…Upon visible light irradiation, the photoexcited electrons from ruthenium(II) could be injected to the conduction band of titania, which could be taken up by the substrates or captured to form strong oxidizing species for further reactions (9). performance (21,24,25). In our previous investigation, two kinds of modifiers were adopted to fabricate titania, e.g., silver nanoparticles (Ag NPs) plus gold nanoparticles (Au NPs), and ruthenium(II) complex plus Au NPs (26,27).…”

Design and Application of Magnetic Photocatalysts for Water Treatment. The Effect of Particle Charge on Surface Functionality

“…Recent studies have shown that photoactivity of P25 exceeds that of anatase in several reaction systems [41,42]. Previously, we have also reported that TiO 2 P25, which is a mixture of anatase and rutile phases exhibited higher efficiency of phenol, pyridine and 4-heptanone degradation compared to commercial anatase particles TiO 2 ST-01 and anatase obtained from titanium isopropoxide (TIP) and titanium butoxide (TBT) hydrolysis in aqueous phase [43,44]. Therefore, the lower photocatalytic activity of BaFe 12 O 19 /SiO 2 /TiO 2 _2 nanocomposite results from the properties of the photocatalytic layer instead of the magnetic core behavior.…”