博文

目前显示的是 一月, 2017的博文

Nanoporous Tungsten Oxide Electrode

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Electrochemical oxidation preparing nanoporous tungsten oxide electrode: 1) Treating method for tungsten foil: Firstly cut it into 10mm x 15mm pieces, using waterproof abrasive to polish it, then clean it with acetone, isopropanol, methyl alcohol and deionized water ultrasound cleaning for 15min, blow it with nitrogen gas. 2) Use tungsten foil as anode, Pt foil of 10 x 15mm as counter electrode, put them into electrobath, the distance between two electrodes is 25mm. Then put electrobath in water bath of constant temperature, adjust the bath temperature to control the reaction temperature. The reacting area is 0.88cm2. Adding a certain amount of ready-prepared 1mol/L(NH 4 ) 2 SO 4  solution electrolyte with different concentration of NH 4 F. 3) Clean the ready-prepared WO 3  nanoporous thin film with deionized water, blow-dry with nitrogen gas in the air and put them in muffle furnace, the heating rate is 5℃/min, cool it down to room temperature, then packed it to nanoporous tungst

Zn Modified Tungsten Oxide Thin Film Electrode

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To promote the photoelectrochemical property, we usually take the following methods: (1) Loading precious simple metal substance such as Pt, Ag, Au. Lay WO 3  over FTO with Ag grid, the testing photocurrent density is two times than the one without Ag. (2) Doping certain amount of metal ion or non-metal ion in tungsten oxide . Doping Ta 5+  in WO 3  photo electrode, the experiment shows that photoelectric conversion rate of doping electrode is much higher. (3) Recombine WO 3  with other inorganic semiconductor material, use impregnation method to prepare CuO/WO 3  composite material. It turns out that CuO/WO 3  shows better photo catalytic ethylal. (4) Recombine WO3 with organic material. Prepare PBrT/WO 3  and PMOT/WO 3  composite material. After testing it shows that the composite one has better electrochemical property. This paper mainly focuses on the research of Zn affects WO 3  thin film photoelectrode photoelectrochemical property. Use simple cathode electro deposition-impr

Highest Performing Tungsten Disulfide Brings Flexible 2D Circuits Closer

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In an e-mail interview with IEEE Spectrum, Shahrjerdi explained that the resulting tungsten disulfide provided a large energy bandgap (2.0 electron volts). Its charge carriers also had a small effective mass: the smaller the effective mass the higher the carrier mobility. “The carrier mobility of our film is 2-3 times better than the best reports in the literature,” said Shahrjerdi. But there’s a catch: it’s tricky to develop a process that will lead to large-area synthesis of device quality TMDs. Now researchers at New York University’s (NYU) Tandon School of Engineering may have taken a big step toward closing down this issue with a new manufacturing process for tungsten disulfide that resulted in highest quality ever reported for the material. In research described in Applied Physics Letters, the scientists made some variations on the process known as chemical vapor deposition (CVD). In CVD, gaseous reactants are introduced into a furnace to form a film on a metal substrate

Tungsten Oxide as Rewritable Material Helps Reduce Paper Waste

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Even in today’s digital age, the world still relies on paper and ink, most of which ends up in landfills or recycling centers. To reduce this waste, scientists have now developed a low-cost, environmentally friendly way to create printed materials with rewritable paper, which is made out of tungsten oxide and a common polymer used in medicines and food. The U.S. has been working to reduce paper waste by increasing recycling efforts for years. According to the Environmental Protection Agency, more paper is now recovered for recycling than almost all other materials combined. This saves energy, water, landfill space and greenhouse gas emissions. But even more waste could be avoided if consumers could reuse paper many times before recycling or trashing it. So far, however, such products under development often are made with toxic, expensive organic dyes. The researchers created a film by mixing low-toxicity tungsten oxide with polyvinyl pyrrolidone. To "print" on i

Tungsten Oxide in Polymer Electrolyte Fuel Cell Electrodes

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There is an experiment the scientists have done. Thin films of tungsten oxide  and Pt on tungsten oxide were evaporated onto the microporous layer of a gas diffusion layer (GDL) and served as model electrodes in the polymer electrolyte fuel cell (PEFC) as well as in liquid electrolyte measurements. In order to study the effects of introducing tungsten oxide in PEFC electrodes, precise amounts of tungsten oxide (films ranging from 0 to 40 nm) with or without a top layer of Pt (3nm) were prepared. The structure of the thin-film model electrodes was characterized by scanning electron microscopy and X-ray photoelectron spectroscopy prior to the electrochemical investigations. The impact of Nafion in the electrode structure was examined by comparing samples with and without Nafion solution sprayed onto the electrode. Fuel cell measurements showed an increased amount of hydrogen tungsten bronzes formed for increasing tungsten oxide thicknesses and that Pt affected the intercalation

Tungsten Oxide and Heteropoly Acid-Based Systems for the Catalysts in PEM Fuel Cell Cathodes

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There is an experiment done by the scientists. The objective is to improve electrocatalyst and membrane electrode assembly (MEA) durability and activity through the use of Pt/ tungsten oxide and Pt/HPA-C (heteropoly acid) modifications to approach automotive proton exchange membrane PEM fuel cell cathodes activity targets (0.44 mA/mg Pt) and durability targets (5,000 h/10 y). Our target is to synthesize alternative supports such as tungsten oxide and HPA-functionalized carbon blacks and to evaluate them for improved corrosion resistance while maintaining or improving activity in comparison to conventional Pt/C supports. Studies are first being conducted in rotating disk electrode (RDE) setups due to the small quantity of materials synthesized and will be followed by testing in fuel cells. The mass activity of ALD-deposited Pt/ tungsten oxide improved to ~175 mA/mg when measured in RDE halfcells. This activity is a significant improvement but falls short of the activity of