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Ag TiO2

Yen-Chi Chen, Kuo-Pin Yu
The antimicrobial efficacy of silver nanoparticles (AgNPs) is influenced by many factors, including the particle size, AgNP oxidation state and support materials. In this study, AgNPs are synthesized and supported by two types of TiO2 powders (P25 and Merck TiO2) using two heat-treatment temperatures (120 and 200°C). The formation of well-dispersed AgNPs with diameters ranging from 3.2 to 5.7nm was confirmed using transmission electron microscopy. X-ray photoelectron spectroscopy and X-ray diffraction indicated that the majority of the AgNPs were reduced from Ag(+) to Ag(0) at 200°C...
March 18, 2017: Colloids and Surfaces. B, Biointerfaces
Qingbin Fan, Pengcheng Huo, Daopeng Wang, Yuzhang Liang, Feng Yan, Ting Xu
Conventional metasurface reflector-arrays based on metallic resonant nanoantenna to control the wavefront of light for focusing always suffer from strong ohmic loss at optical frequencies. Here, we overcome this challenge by constructing a non-resonant, hybrid dielectric-metal configuration consisting of TiO2 nanofins associated with an Ag reflector substrate that provides a broadband response and high polarization conversion efficiency in the visible range. A reflective flat lens based on this configuration shows an excellent focusing performance with the spot size close to the diffraction limit...
March 23, 2017: Scientific Reports
Duoduo Wu, Jianzhong Ma, Yan Bao, Wanzhao Cui, Tiancun Hu, Jing Yang, Yuanrui Bai
Porous Ag/TiO2/Au coatings with excellent multipactor suppression were prepared by fabrication of porous Ag surface through two-step wet chemical etching, synthesis of TiO2 coatings by electroless-plating-like solution deposition and deposition of Au coatings via electroless plating. Porous structure of Ag surface, TiO2 coatings on porous Ag surface and Au coatings on porous Ag/TiO2 surface were verified by field-emission scanning electron microscopy, the composition and crystal type of TiO2 coatings was characterized by X-ray photoelectron spectroscopy and X-ray diffraction...
March 10, 2017: Scientific Reports
Yeoseon Choi, Min Seok Koo, Alok D Bokare, Dong-Hyo Kim, Detlef W Bahnemann, Wonyong Choi
We investigated a sequential photocatalysis-dark reaction, wherein organic pollutants were degraded on Ag/TiO2 under UV irradiation and the dark reduction of hexavalent chromium (Cr(VI)) was subsequently followed. The photocatalytic oxidation of 4-chlorophenol (4-CP), a test organic substrate, induced the generation of degradation intermediates and the storage of electrons in Ag/TiO2 which were then utilized for reducing Cr(VI) in the post-irradiation period. The dark reduction efficiency of Cr(VI) was much higher with Ag/TiO2 (87%), compared with bare TiO2 (27%) and Pt/TiO2 (22%)...
March 9, 2017: Environmental Science & Technology
Koichiro Saito, Kenji Setoura, Syoji Ito, Hiroshi Miyasaka, Yoshitaka Mitsuda, Tetsu Tatsuma
When plasmonic nanoparticles are placed on a highly refractive semiconductor substrate, we can expect three different effects: (i) resonance mode splitting, (ii) asymmetric light scattering based on the split modes, and (iii) site-selective nanoetching due to plasmon-induced charge separation (PICS) at the nanoparticle-semiconductor interface. Here, we develop novel photofunctional materials by taking advantage of those three effects. More specifically, we control the asymmetric scattering of Ag nanocubes on TiO2 by PICS, so as to develop materials for photodrawing of one-way visible translucent images and multicolor scattering images...
March 15, 2017: ACS Applied Materials & Interfaces
Xing Wei, Pascal Sugri Nbelayim, Go Kawamura, Hiroyuki Muto, Atsunori Matsuda
A layer of TiO2 nanotube (TNT) arrays with a thickness of 13 μm is synthesized by a two-step anodic oxidation from Ti metal foil. Surface charged Ag nanoparticles (NPs) are prepared by chemical reduction. After a pretreatment of the TNT arrays by acetone vapor, Ag NP filled TNT arrays can be achieved by electrophoretic deposition (EPD). Effects of the applied voltage during EPD such as DC-AC difference, frequency and waveform are investigated by quantitative analysis using atomic absorption spectroscopy. The results show that the best EPD condition is using DC 2 V + AC 4 V and a square wave of 1 Hz as the applied voltage...
March 3, 2017: Nanotechnology
V M Zhyrovetsky, D I Popovych, S S Savka, A S Serednytski
Gas sensing properties of metal oxide nanopowders (ZnO, TiO2, WO3, SnO2) with average diameters of 40-60 nm were analyzed by room-temperature photoluminescence spectroscopy. The influence of gas environment (O2, N2, H2, CO, CO2) on the emission intensity was investigated for metal oxide nanopowders with surface doped by impurities (Pt, Ag, Au, Sn, Ni or Cu). Established physicochemical regularities of modification of surface electronic states of initial and doped nanopowders during gas adsorption. The nature of metal oxide nanopowder gas-sensing properties (adsorption capacity, sensitivity, selectivity) has been established and the design and optimal materials for the construction of the multi-component sensing matrix have been selected...
December 2017: Nanoscale Research Letters
Ming-Hua Yeh, Po-Hsun Chen, Yi-Ching Yang, Guan-Hong Chen, Hsueh-Shih Chen
The atomic layer deposition (ALD) technique is applied to coat Ag nanowires (NWs) with a highly uniform and conformal TiO2 layer to improve the stability and sustainability of Ag NW transparent conductive films (TCFs) at high temperatures. The TiO2 layer can be directly deposited on Ag NWs with a surface polyvinylpyrrolidone (PVP) coat that acts a bed for TiO2 seeding in the ALD process. The ALD TiO2 layer significantly enhances the thermal stability at least 100 fold when aged between 200-400 °C and also provides an extra function of violet-blue light filtration for Ag NW TCFs...
March 20, 2017: ACS Applied Materials & Interfaces
Ying Zhou, Haijun Wang, Ying Zhuo, Yaqin Chai, Ruo Yuan
In this work, a ferrocene (Fc)-driven light switch biosensor for ultrasensitive detection of amyloid-β (Aβ) was designed by utilizing the highly efficient electrochemiluminescent nanomaterials of silver nanoclusters/titanium oxide nanoflowers (Ag NCs/TiO2 NFs) as signal labels. Through combining the TiO2 NFs as the coreaction accelerator and dissolved O2 as the intrinsic coreactant to in situ generate the strong oxidizing intermediate radical OH(•), the electrochemiluminescence (ECL) of Ag NCs on the TiO2 NFs surface could be significantly promoted in comparison with that of pure Ag NCs in solution...
March 6, 2017: Analytical Chemistry
Zhengjian Li, Zongzhao Sun, Zhiqiang Duan, Rui Li, Yanli Yang, Jingyi Wang, Xiaoxia Lv, Wei Qi, Hua Wang
In the present work, a facile and efficient fabrication method has been developed for creating super-hydrophobic coatings of silver-doped TiO2@polycarbonate (TiO2 (Ag)@PC) on the substrates of different materials with photocatalytic self-cleaning performances simply by the "dipping and drying" process. The substrates were first patterned with glue and then deposited with the dopamine-capped TiO2 (Ag)@PC (DA-TiO2 (Ag)@PC) nanocomposites, followed by the further etching with dimethylbenzene. The so prepared super-hydrophobic E-DA-TiO2(Ag)@PC coatings could present the lotus leaf-like porous architectures, high adhesion stability, and especially the visible-light photocatalysis for organic contaminant degradation, thus promising the wide outdoor and indoor applications like water proofing, metal erosion protection, and surface self-cleaning...
February 20, 2017: Scientific Reports
Shams T Khan, Ajmaluddin Malik, Rizwan Wahab, Omar H Abd-Elkader, Maqusood Ahamed, Javed Ahmad, Javed Musarrat, Maqsood A Siddiqui, Abdulaziz A Al-Khedhairy
Although the antimicrobial activity of the engineered nanoparticles (NPs) is well known, the biochemical mechanisms underlying this activity are not clearly understood. Therefore, four NPs with the highest global production, namely SiO2, TiO2, ZnO, and Ag, were synthesized and characterized. The synthesized SiO2, TiO2, ZnO, and Ag NPs exhibit an average size of 11.12, 13.4, 35, and 50 nm, respectively. The antimicrobial activity of the synthesized NPs against bacteria and fungi were also determined. NPs-mediated inhibition of two very important enzymes, namely urease and DNA polymerase, is also reported...
February 20, 2017: Acta Microbiologica et Immunologica Hungarica
Arixin Bo, Jose Alarco, Huaiyong Zhu, Eric R Waclawik, Haifei Zhan, YuanTong Gu
Construction of nanoarchitectures requires techniques like joint formation and trimming. For ceramic materials, however, it is extremely difficult to form nanojoints by conventional methods like merging. In this work, we demonstrate that ceramic titanate nanowires (NWs) can be joined by spot melting under electron beam (e-beam) irradiation (EBI). The irradiation fuses the contacted spot of titanate NWs yielding an intact nanojoint. Nanojoints with different morphologies can be produced. The joint structures consist of titanium dioxide (TiO2) rutile, anatase, and titanate phases in the direction away from the e-beam melting spot...
March 2, 2017: ACS Applied Materials & Interfaces
Na Xu, Hao Cheng, Jiangwen Xu, Feng Li, Biao Gao, Zi Li, Chenghao Gao, Kaifu Huo, Jijiang Fu, Wei Xiong
Antibiotic-resistant bacteria have become a major issue due to the long-term use and abuse of antibiotics in treatments in clinics. The combination therapy of antibiotics and silver (Ag) nanoparticles is an effective way of both enhancing the antibacterial effect and decreasing the usage of antibiotics. Although the method has been proved to be effective in vitro, no in vivo tests have been carried out at present. Herein, we described a combination therapy of local delivery of Ag and systemic antibiotics treatment in vitro in an infection model of rat...
2017: International Journal of Nanomedicine
Tian Yin Sun, Denise M Mitrano, Nikolaus A Bornhöft, Martin Scheringer, Konrad Hungerbühler, Bernd Nowack
The need for an environmental risk assessment for engineered nanomaterials (ENM) necessitates the knowledge about their environmental emissions. Material flow models (MFA) have been used to provide predicted environmental emissions but most current nano-MFA models consider neither the rapid development of ENM production nor the fact that a large proportion of ENM are entering an in-use stock and are released from products over time (i.e., have a lag phase). Here we use dynamic probabilistic material flow modeling to predict scenarios of the future flows of four ENM (nano-TiO2, nano-ZnO, nano-Ag and CNT) to environmental compartments and to quantify their amounts in (temporary) sinks such as the in-use stock and ("final") environmental sinks such as soil and sediment...
February 16, 2017: Environmental Science & Technology
Li Xu, Gaorui Liang, Ming Yin
A distinctive SnO2Sb electrode with highly ordered Nb doped TiO2 nanotubes sheet as a new substrate, obtained by NbTi alloy anodization, is prepared by pulse electrochemical deposition for the first time as electrocatalytic oxidation anode for wastewater treatment. The novel electrode has a larger surface area and smaller crystallite particles than conventional SnO2Sb electrodes as obtained from the analysis of scanning electron microscopy and X-ray diffraction. Compared with Ti/SnO2Sb and Ti/TiO2-NTs/SnO2Sb prepared by pulse electrochemical deposition, the electrode modified by NbTiO2-NTs has the higher oxygen evolution potential of 2...
January 17, 2017: Chemosphere
Afnan Alghannam, Christopher L Muhich, Charles B Musgrave
Titanium oxide is often decorated with metal nano-particles and either serves as a catalyst support or enables photocatalytic activity. The activity of these systems degrades over time due to catalytic particle agglomeration and growth by Ostwald ripening where adatoms dissociate from metal particles, diffuse across the surface and add to other metal particles. In this work, we use density functional theory calculations to study the diffusion mechanisms of select group VIII and 1B late-transition metal adatoms commonly used in catalysis and photocatalysis (Au, Ag, Cu, Pt, Rh, Ni, Co and Fe) on the anatase TiO2(101) surface...
January 26, 2017: Physical Chemistry Chemical Physics: PCCP
Baranidharan Sundaram, Arun Kumar
This study evaluated the influence of metal oxide nanoparticles (NPs) (Ag2O, TiO2) and their mixture on activated sludge for 180 days. When tested, a mixture of NPs at 1 and 10 mg/L had greater impact than individual NPs, in which maximum reduction in chemical oxygen demand (COD) elimination (76.3%) was observed after 150 days for 1 mg/L (500 mg/L COD concentration) and after 180 days (70.2%) for 10 mg/L (250 mg/L COD concentration). TiO2 had higher inhibition on COD reduction than Ag2O NPs at 1 and 10 mg/L...
January 2017: Water Science and Technology: a Journal of the International Association on Water Pollution Research
Emrah Sefik Abamor, Adil M Allahverdiyev, Melahat Bagirova, Miriam Rafailovich
Currently, the treatment of leishmaniasis is increasingly insufficient as current antileishmanial drugs have many disadvantages such as toxic side effects, high cost, and growing drug resistance. In order to overcome these disadvantages, researchers have recently focused on combination therapy by using pentavalent antimonials in conjunction with other antileihmanial compounds. Our previous study found that TiO2@Ag nanoparticles (TiAgNps) demonstrated significant antileishmanial effects. However, a lethal dose of TiAgNps on L...
May 2017: Acta Tropica
Jinxia Xu, Zhenhuan Wang, Wenqing Li, Xingang Zhang, Dong He, Xiangheng Xiao
High specific surface area three-dimensional pine tree-like hierarchical TiO2 nanotube array films loaded with Ag nanoparticles were successfully prepared by one-step hydrothermal reaction combining with simple and feasible magnetron sputtering. The composite Ag/TiO2-branched nanotube arrays show outstanding photocatalytic property, which is attributed to the boost of plasmonic enhancement carrier generation and separation, higher specific surface area, higher organic pollutant absorption, faster charge transport, and superior light-harvesting efficiency for efficient charge collection...
December 2017: Nanoscale Research Letters
Olga Malev, Polonca Trebše, Małgorzata Piecha, Sara Novak, Bojan Budič, Miroslav D Dramićanin, Damjana Drobne
Nano-sized cerium dioxide (CeO2) particles are emerging as an environmental issue due to their extensive use in automobile industries as fuel additives. Limited information is available on the potential toxicity of CeO2 nanoparticles (NPs) on terrestrial invertebrates through dietary exposure. In the present study, the toxic effects of CeO2 NPs on the model soil organism Porcellio scaber were evaluated. Nanotoxicity was assessed by monitoring the lipid peroxidation (LP) level and feeding rate after 14-days exposure to food amended with nano CeO2...
February 2017: Archives of Environmental Contamination and Toxicology
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