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Kaituo Liu, James Pritchard, Li Lu, Robbert van Putten, M W G M Tiny Verhoeven, Mike Schmitkamp, Xiaoming Huang, Laurent Lefort, Christopher J Kiely, Emiel J M Hensen, Evgeny A Pidko
The addition of Re to Ni on TiO2 yields efficient catalysts for the hydrogenation of acids and esters to alcohols under mild conditions. Rhenium promotes the formation of atomically dispersed and sub-nanometre-sized bimetallic species interacting strongly with the oxide support.
August 16, 2017: Chemical Communications: Chem Comm
Xiaoning Ren, Zhiyi Hu, Jun Jin, Liang Wu, Chao Wang, Jing Liu, Fu Liu, Min Wu, Yu Li, Gustaaf Van Tendeloo, Bao-Lian Su
Phase-junction between cocatalyst and semiconductor host is quite effective to enhance the photocatalytic activity, and is widely studied while the report on the phase-juncted cocatalyst is still rare. In this work, we report the deposition of the Pt/PtO phase-juncted nanodots as cocatalyst via NaOH modification of an interconnected meso-macroporous TiO2 network with high surface area and inner-particle mesopores to enhance the performance of photocatalytic H2 production. Our results show that NaOH modification can largely influence the Pt/PtO phase-juncted nanodots formation and dispersity...
August 16, 2017: ACS Applied Materials & Interfaces
Valeria Saavedra Becerril, Elin Sundin, Mokhtar Mapar, Maria Abrahamsson
A simple method for the preparation of patterned dye-sensitized SnO2-TiO2 thin films, designed to prolong the lifetime of the interfacial charge separated state is presented. Using microfluidic technology, the thin films were sensitized with the organic sensitizer D35 such that they contain SnO2-TiO2 areas with dye and SnO2 dye-free areas at which injected electrons can be accumulated. Single wavelength transient absorption spectroscopy confirmed significantly extended charge separation lifetime at the dye-semiconductor interface...
August 16, 2017: Physical Chemistry Chemical Physics: PCCP
Manuel Salado, Ramesh K Kokal, Laura Calio, Samrana Kazim, Melepurath Deepa, Shahzada Ahmad
Triple cation based perovskite solar cells offer enhanced moisture tolerance and stability compared to mixed perovskites. Slight substitution of methyl ammonium or formamidinium cation by cesium (Cs(+)), was also reported to eliminate halide segregation due to its smaller size. To elucidate the device kinetics and understand the role of the Cs, we undertook different modes of scanning probe microscopy and electrochemical impedance spectroscopy (EIS) experiments. Kelvin probe force microscopy revealed that the incorporation of the Cs cation increases the contact potential difference (CPD), this CPD further increases when Spiro-OMeTAD is used as a hole transport material...
August 16, 2017: Physical Chemistry Chemical Physics: PCCP
Marko Kete, Olena Pliekhova, Lev Matoh, Urška Lavrenčič Štangar
A compact reactor for photocatalytic oxidation and photocatalytic ozonation water treatment was developed and evaluated by using four model pollutants. Additionally, combinations of pollutants were evaluated. Specially produced Al2O3 porous reticulated monolith foams served as TiO2 carriers, offering a high surface area support. UV lamps were placed in the interior to achieve reduced dimensions of the reactor (12 cm in diameter × 20 cm in height). Despite its small size, the overall photocatalytic cleaning capacity was substantial...
August 15, 2017: Environmental Science and Pollution Research International
Diogo José Horst, Sergio Mazurek Tebcherani, Evaldo Toniolo Kubaski, Rogério de Almeida Vieira
This experimental study investigates the bioactive potential of filaments produced via hot melt extrusion (HME) and intended for fused deposition modeling (FDM) 3D printing purposes. The oleo-gum-resins from benzoin, myrrha, and olibanum in pure state and also charged with 10% of metal oxide nanoparticles, TiO2, P25, Cu2O, and MoO3, were characterized by ultraviolet-visible (UV-Vis) and Fourier transform infrared (FTIR) spectroscopy, energy-dispersive X-ray microanalysis (EDXMA), scanning electron microscopy (SEM), and differential scanning calorimetry (DSC)...
2017: Bioinorganic Chemistry and Applications
Degao Wang, Matthew V Sheridan, Bing Shan, Byron H Farnum, Seth L Marquard, Benjamin D Sherman, Michael S Eberhart, Animesh Nayak, Christopher Dares, Atanu Das, R Morris Bullock, Thomas J Meyer
In a Dye Sensitized Photoelectrosynthesis Cell (DSPEC) the relative orientation of the catalyst and chromophore plays an important role in determining the device efficiency. Here we introduce a new, robust atomic layer deposition (ALD) procedure for the preparation of molecular chromophore-catalyst assemblies on wide bandgap semiconductors. In this procedure, solution deposited, phosphonate derivatized metal complexes on metal oxide surfaces are treated with reactive metal reagents in the gas phase by ALD to form an outer metal ion bridging group which can bind a second phosphonate containing species from solution to establish a R1-PO2-O-M-O-PO2-R2 type surface assembly...
August 15, 2017: Journal of the American Chemical Society
Manisha Yadav, Asha Yadav, Rohan Fernandes, Yaksh Popat, Michele Orlandi, Alpa Dashora, D C Kothari, Antonio Miotello, B L Ahuja, Nainesh Patel
Recombination of photogenerated charges is the main factor affecting the photocatalytic activity of TiO2. Here, we report a combined strategy of suppressing both the bulk as well as the surface recombination processes by doping TiO2 with tungsten and forming a nanocomposite with reduced graphene oxide (rGO), respectively. Sol-gel method was used to dope and optimize the concentration of W in TiO2 powder. UV-Vis, XPS, PL and time resolved PL spectra along with DFT calculations indicate that W(6+) in TiO2 lattice creates an impurity level just below the conduction band of TiO2 to act as a trapping site of electrons, which causes to improve the lifetime of the photo-generated charges...
August 12, 2017: Journal of Environmental Management
Cheng Tan, Wen-Xiong Wang
Increasing applications of titanium dioxide nanoparticles (nano-TiO2) have intensified the risk of environmental contamination. Since nano-TiO2 can absorb metals and be consumed as 'food' by zooplankton but also can interact with phytoplankton, they could significantly disturb the existing metal assimilation patterns. In the present study, we quantified the dietary assimilation of Cd and Zn from nano-TiO2 and algae (Chlamydomonas reinhardtii) at comparable particle concentrations as well as in complex food environment (variable food quality and quantity) in a freshwater zooplankton Daphnia magna using the radiotracer technique...
August 11, 2017: Environmental Pollution
Xiaoyan Jin, Joohyun Lim, Yoonhoo Ha, Nam Hee Kwon, Hyeyoung Shin, In Young Kim, Nam-Suk Lee, Myung Hwa Kim, Hyungjun Kim, Seong-Ju Hwang
The effect of the catalyst morphology on the growth of carbon nanotubes (CNT) on nanostructured transition metal oxides was investigated to study a novel low-temperature synthetic route to functional CNT-transition metal oxide nanocomposites. Among several nanostructured manganese oxides with various morphologies and structures, only exfoliated 2D nanosheets of layered MnO2 acted as an effective catalyst for the chemical vapor deposition of CNT at low temperatures of 400-500 °C, which emphasizes the critical role of the catalyst morphology in CNT growth...
August 15, 2017: Nanoscale
Mingming Zou, Lu Feng, Zhang Bingxue, Xinxin Zhou, Minghui Yang
A kind of surface complex (Triethylamine and mesoporous W-N-TiO2 microspheres with large surface area: 117.5 m2g-1) catalysis were achieved via visible-light photoredox catalysis. Triethylamine behaves as a true redox mediator due to donating ability seems to be highly favorable. With lower bandgap (2.43 eV) and more positive level of VBM (2.905 V), W-N-TiO2 sample has ability to play active catalytic role yielding excellent conversion of the selective oxidation of thioanisole (75.16 %) within 12 h visible light irradiation...
August 15, 2017: Nanotechnology
Haider Ali, Xinbo Yang, Klaus Weber, Winston V Schoenfeld, Kristopher O Davis
In this study, the cross-section of electron-selective titanium oxide (TiO2) contacts for n-type crystalline silicon solar cells were investigated by transmission electron microscopy. It was revealed that the excellent cell efficiency of 21.6% obtained on n-type cells, featuring SiO2/TiO2/Al rear contacts and after forming gas annealing (FGA) at 350°C, is due to strong surface passivation of SiO2/TiO2 stack as well as low contact resistivity at the Si/SiO2/TiO2 heterojunction. This can be attributed to the transformation of amorphous TiO2 to a conducting TiO2-x phase...
August 15, 2017: Microscopy and Microanalysis
Seung-Hyun Kim, Mihyun Lee, Mira Cho, Il-Sun Kim, Kook In Park, Haeshin Lee, Jae-Hyung Jang
Devising efficient gene delivery systems is crucial to enhancing the therapeutic efficacy of gene-cell therapy approaches. Herein, inverted quasi-spherical (iQS) droplet systems, which enhance gene delivery efficiencies by reducing the path lengths of gene vectors, mediating motions of vectors at early stages, and raising the contact frequencies of vectors with cells, are developed by adopting the principle of 3D hanging-drop cell culture. Micrometer-sized polydopamine (pDA) holes are created on superhydrophobic titanium isopropoxide (TiO2 )-coated substrates by physical scraping; droplets are loaded on the pDA holes, and inversion of the substrate generates iQS droplets with large contact angles...
August 15, 2017: Macromolecular Bioscience
José I Martínez, Fernando Flores, José Ortega, Sylvie Rangan, Charles M Ruggieri, Robert A Bartynski
In this perspective we present a comprehensive analysis of the energy level alignment at the interface between an organic monolayer (organic = perylenetetracarboxylic dianhydride, PTCDA, zinc tetraphenylporphyrin, Zn-TPP, and tetracyanoquinodimethane, TCNQ) and a prototypical oxide surface, TiO2(110), looking for universal behaviours. PTCDA shows a physisorbed interaction with TiO2 and a small interface dipole potential with its highest occupied molecular orbital (HOMO) energy level located in the oxide energy gap and the lowest occupied molecular orbital (LUMO) energy level located above the oxide conduction band minimum, EC...
August 15, 2017: Physical Chemistry Chemical Physics: PCCP
Jin-Ling Luo, Shi-Fa Wang, Wei Liu, Cheng-Xiang Tian, Ju-Wei Wu, Xiao-Tao Zu, Wei-Lie Zhou, Xiao-Dong Yuan, Xia Xiang
Three kinds of Al-TiO2 samples and pure TiO2 samples were synthesized via a modified polyacrylamide gel route using different aluminum salts, including Al2(SO4)3∙18H2O, AlCl3, and Al(NO3)3∙9H2O under identical conditions. The influence of different aluminum salts on the phase purity, morphologies, thermal stability of anatase and photocatalytic properties of the as-prepared Al-TiO2 nanoparticles were studied. The energy gap (Eg) of Al-TiO2 nanoparticles decreases due to Al ion doping into TiO2. The photocatalytic activities of the Al-TiO2 samples were investigated by the degradation of acid orange 7 dye in aqueous solution under simulated solar irradiation...
August 14, 2017: Scientific Reports
Jiafei Su, Guohong Yang, Cuilian Cheng, Chen Huang, He Xu, Qinfei Ke
Hierarchically structured, nanoparticle-on-nanofiber composite membranes were successfully prepared by electrospray of titanium dioxide (TiO2) suspensions and electrospinning of polyacrylonitrile (PAN) solution simultaneously. The results showed that the TiO2 nanoparticles were highly dispersed on the surface of PAN nanofibers to construct hierarchical nanostructures, which could not only endow the composite membrane with high photocatalytic activity but also further improve the filter efficiency of the composite membrane...
July 29, 2017: Journal of Colloid and Interface Science
Xin Zhao, Weiwei Zhang, Chuchu Peng, Yujie Liang, Wenzhong Wang
In this work, the semiconductor TiO2 nanowires were successfully coupled with plasmonic metal Ag nanoparticles to fabricate hybrid nanostructures with enhanced sensitive Raman substrate. The SERS activities of fabricated hybrid nanostructures were evaluated by detecting the Raman signals of R6G molecules. The fabricated TiO2/Ag nanowire/nanoparticle hybrid nanostructures show sensitive detection ability for R6G molecules. Based on the band structures of Ag nanoparticle, TiO2 nanowire and R6G molecule, the enhanced sensitive SERS activities of hybrid nanostructures is ascribed to an efficient charge transfer process, in which the photogenerated electrons transfer to the conduction band of TiO2 nanowires from metal Ag nanoparticles, and then to LUMO level of R6G molecules, leading to enhanced SERS activities...
August 8, 2017: Journal of Colloid and Interface Science
Shayan MiarAlipour, Donia Friedmann, Jason Scott, Rose Amal
This article reviews two interrelated areas of research: the first is the use of TiO2-supported adsorbent materials as enhanced heterogeneous photocatalysts and their application to various reactions for organic pollutant removal from air and water; the second is the combination of adsorbent materials with TiO2 photocatalysts which aims to efficiently regenerate adsorbent materials using illumination. By reviewing both areas of research, the following topics are covered; (i) photocatalytic activation of TiO2; (ii) related properties of photocatalytic TiO2; (iii) shortcomings of photocatalytic processes; (iv) preparation methods of composite TiO2/adsorbent materials and their photocatalytic performance; (v) properties of common adsorbents and their applications for pollutant removal from air and water; (vi) adsorbent regeneration methods and their economic and operational issues; (vii) conclusions and future outlooks...
August 5, 2017: Journal of Hazardous Materials
Xiaolei Wang, Peng Li, Xiao Xia Han, Yasutaka Kitahama, Bing Zhao, Yukihiro Ozaki
A number of recent studies have focused on improving the performance of dye-sensitized solar cells (DSSCs). Cells with a ZnO-TiO2/N3/Ag structure have attracted particular attention because of their excellent power conversion efficiencies. Using a dendritic crystal ZnO-TiO2 composite semiconductor and Ag in conjunction leads to different charge-transfer (CT) processes, and this is the main theoretical basis for the improvement of DSSC performances. Thus, in the present study, TiO2/N3, ZnO/N3, ZnO-TiO2/N3, TiO2/N3/Ag, ZnO/N3/Ag, and ZnO-TiO2/N3/Ag assemblies have been fabricated and their CT processes have been monitored by using surface-enhanced Raman scattering (SERS) spectra, with particular focus on the differences caused by the synergistic effect of the ZnO-TiO2 component...
August 14, 2017: Nanoscale
John Ciro, Santiago Mesa, Juan Felipe Montoya, Jose Ignacio Uribe, Rafael Betancur, Franklin Jaramillo
Optimization of the interface between the electron transport layer (ETL) and hybrid perovskite is crucial to achieve high performance perovskite solar cell (PSC) devices. Fullerene-based compounds have attracted attention as modifiers on the surface properties of TiO2, the archetypal ETL in regular n-i-p PSCs. However, the partial solubility of fullerenes in the aprotic solvents used for perovskite deposition hinders its application to low-temperature solution-processed PSCs. In this work, we introduce a new method for fullerene modification of TiO2 layers derived from nanoparticles (NPs) inks...
August 14, 2017: ACS Applied Materials & Interfaces
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