Photocatalytic activity of Ag nanoparticle-dispersed N-TiO₂ nanofilms prepared by magnetron sputtering

Abstract

Table of contents entryBack-scattered electron image and secondary electron image of a scraped Ag 50nm/N-TiO 2 nanofilm after the heat treatment at 400 o C. Dependence of the degradation rate of the TiO 2 -based nanofilms on the number of cycles for the photodegradation of MB. The degradation rate of the TiO 2 -based nanofilms decreases with the number of cycles. AbstractUsing magnetron sputtering, pure TiO 2 nanofilms and Ag/TiO 2 bilayer nanofilms with N were deposited on glass substrates. Heat-treatment of the Ag/N-TiO 2 nanofilms at 400 o C led to the formation of Ag nanoparticles, which were dispersed inside the TiO 2 films as well as on the free surface of the TiO 2 films. The photocatalytic activity of the Ag/N-TiO 2 nanofilms with the dispersion of Ag nanoparticles was examined by UV-vis diffuse reflectance spectroscopy.The rate constants for the photodegradation of methylene blue (MB) in the aqueous solutions of MB with N-TiO 2 -based nanofilms are about one order larger than that of self-degradation and that with only pure TiO 2 nanofilms. The rate constants for the photodegradation of the aqueous solutions of MB with the Ag/N-TiO 2 nanofilms are larger than that with the N-TiO 2 nanofilms. The Ag nanoparticles improve the photocatalytic activity of TiO 2 films possibly through the surface plasmon absorption effect of Ag nanoparticles which activates photo-generated charge carriers through the transfer of plasmonic energy. 9 Ti(IV) state. For the pure TiO 2 nanofilms, the peaks in the Ti 2p spectrum associated with the binding energies of Ti 2p 3/2 and Ti 2p 1/2 levels are at 457.8 and 463.5 eV 35 , slightly less than the corresponding binding energies of the Ag/N-TiO 2 nanofilms, suggesting the presence of Ti(IV) state. This result confirms a lower electron density of the TiO 2 surface with the presence of Ag nanoparticles. There is a strong interaction between metallic Ag nanoparticles and TiO 2 in the Ag/TiO 2 nanofilms. SEM and EDS analysesBack-scattered electron (BSE) imaging was performed to identify the phases presented in the Ag/N-TiO 2 nanofilms. Figure 3 shows the BSE images, secondary electron (SEM) images, and the corresponding EDS spectrum of the Ag/N-TiO 2 nanofilms. The EDS patterns, as shown in Figure 3, display the peaks of Ti, O, Ag and N, confirming the presence of Ag and N elements in all the Ag/N-TiO 2 nanofilms.

Noble metal-titania hybrid nanoparticle clusters and the interaction to proteins for photo-catalysis in aqueous environments

“…[17,18] In this regard, the emerging field of using plasmonic noble metal nanoparticle (NP) has made promise. [2,3,11,12,[15][16][17][18][19][20][21] By a combination of noble metal NP with TiO 2 -NP, a sufficient utilization of solar energy, which accounts for enhanced photocatalytic activity including near-field, far-field, and charge transfer phenomena, can be achieved simultaneously. [21] In addition, the noble metal NP can be used as electron traps to suppress the recombination of electron-hole pairs in TiO 2 -NP.…”

“…Silver nanoparticle (AgNP) is chosen as the candidate noble metal NP based on its strong characteristic surface plasmon resonance (SPR) in the visible light region. [11,[16][17][18][19][20][21] Our approach is to obtain noble metal NP-decorated TiO 2 -NPC with high quality and desired properties, by which we can effectively improve the photocatalytic activity of noble metal NP-decorated TiO 2 -NPC for the energy and environmental applications. …”

“…[4,5,9,10] The functional response of TiO 2 -NP is fundamentally governed by the generation of charge carrier by photons. [4][5][6][7][8]11] In principle, the positive holes can be used to oxidize the organic compounds, where the negative electrons can be used to reduce the conversion of molecular oxygen to superoxide radical anions in the complete cycle of photo-catalysis. [12][13][14] Therefore, the applications of TiO 2 -NP have extended into a variety of areas of photocatalysis, for example, the photo-decomposition of the toxic components, which has shown to very useful for a variety of environmental applications including the purification of water and air in the environment.…”

Fast diffusion of silver in TiO2 nanotube arrays

“…Titanium dioxide (TiO 2 ) has gained great attention for various applications, such as energy storage [1–8] and photo-assisted reactions [9–14], due to its inherent semiconducting characteristics, chemical stability, high photo-conversion efficiency, non-toxicity and low cost [15–16]. TiO 2 of low-dimensional structures, including nanotubes, nanoparticles, nanorods, mesoporous spheres, nanosheets, nanowires have been synthesized via anodic oxidation, template, and hydrothermal processing to increase the ratio of surface area to volume for the maximization of effective surface area [17].…”

Cauliflower-like CeO2–TiO2hybrid nanostructures with extreme photocatalytic and self-cleaning properties

“…[3][4][5] Beside its various advantages such as low cost, earth abundance, and non-toxicity, high electron-hole recombination rate is one of the main drawbacks of TiO2. 6 In addition, low electron mobility and small diffusion length (for holes) limit the practical use of TiO2 in heterogeneous photocatalytic applications. 7 Doping or decorating TiO2 with metallic elements is one of the common methods to improve its photocatalytic efficiency.…”