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181.
Mild Synthesis of Pt/SnO2/Graphene Nanocomposites with Remarkably Enhanced Ethanol Electro‐oxidation Activity and Durability 下载免费PDF全文
Dr. Yunteng Qu Dr. Yunzhi Gao Dr. Long Wang Dr. Jiancun Rao Dr. Geping Yin 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(1):193-198
We have designed a new Pt/SnO2/graphene nanomaterial by using L ‐arginine as a linker; this material shows the unique Pt‐around‐SnO2 structure. The Sn2+ cations reduce graphene oxide (GO), leading to the in situ formation of SnO2/graphene hybrids. L ‐Arginine is used as a linker and protector to induce the in situ growth of Pt nanoparticles (NPs) connected with SnO2 NPs and impede the agglomeration of Pt NPs. The obtained Pt/SnO2/graphene composites exhibit superior electrocatalytic activity and stability for the ethanol oxidation reaction as compared with the commercial Pt/C catalyst owing to the close‐connected structure between the Pt NPs and SnO2 NPs. This work should have a great impact on the rational design of future metal–metal oxide nanostructures with high catalytic activity and stability for fuel cell systems. 相似文献
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Dariush Souri Mohammad Elahi Mohammad S. Yazdanpanah 《Central European Journal of Physics》2008,6(2):306-310
The ternary 70P2O5-10Li2MoO4-20Li2O and 70P2O5-10Na2MoO4-20Na2O glasses, prepared by the press-melt quenching technique, were studied at temperatures between 298 and 418 K for their high
dc electric field properties. For the above purpose, the effect of a strong electric field on the dc conduction of these amorphous
bulk samples was investigated using the gap-type electrode configuration. At low electric fields, the current-voltage (I — V) characteristics have a linear shape, while at high electric fields (> 103 V/cm), bulk samples show nonlinear effects (nonohmic conduction). Current-voltage curves show increasing departure from Ohm’s
law with increasing current density, leading to critical phenomena at a maximum voltage (threshold voltage), known as switching
(switch from a low-conduction state to a higher-conduction state at threshold voltage). The Pool-Frenkel high-field effect
was observed at electrical fields of about 103–104 V/cm; then the lowering factor of the potential barrier, the high frequency dielectric constant, and the refractive index
of these glasses were determined.
相似文献
184.
Corroded samples, from the steel shell of an industrial evaporator system were investigated. A protective magnetite layer had formed, which subsequently dissolved in localised areas, resulting in failure of the shell. To clarify the mechanisms involved, mild steel samples of similar composition to the steel shell were submerged in the condensate and experiments were performed at room temperature and at 90°C under both static and dynamic conditions for exposure times up to 30 days. Control samples were submerged in deionised water under similar conditions. The dynamic corrosion rates in the industrial condensate were a factor of 2 higher than the rates for the deionised water, whilst static corrosion rates, measured in both media, were lower by a factor of 3 to 4 found for the dynamic experiments. The corrosion products were identified by means of CEMS analyses. The main components were magnetite and oxyhydroxides of iron. Additional to the species mentioned, -Fe2O3, goethite and hematite formed. 相似文献
185.
Melanie J. Heying Mrinmoy Nag William S. Jenks 《Journal of Physical Organic Chemistry》2008,21(11):915-924
Photolysis of substituted thiophene‐S‐oxides in solution results in the formation of either the corresponding thiophene or furan, in addition to uncharacterized materials. No good rationalization is available for the choice of which pathway may predominate, but it is demonstrated that the photolysis of 2,5‐bistrimethylsilylthiopene‐ S‐oxide produces O(3P) in the same manner as the well‐established photolysis of dibenzothiophene‐S‐oxide. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
186.
A discussion on the use of Auger electron spectroscopy as a quantitative tool to determine the growth mode of metals on single crystal oxide surfaces is presented. In the case of Pd grown epitaxially on MgO(100), the three-dimensional character of the growth is easily seen at coverage above one monolayer. However, in the submonolayer regime, and mainly at low substrate temperatures, the AES results are ambiguous. The combination of AES with the more sensitive helium-atom diffraction method allows us to demonstrate that the growth is three-dimensional from the early stages, the particles becoming flatter when the substrate temperature decreases. We compare our results with other growth studies on different metal/oxide systems. At low temperature, the ideal growth modes are not always observed, the final morphology of the films being determined mainly by kinetic effects. Thus a pseudo-Stranski-Krastanov growth mode is often obtained with formation of 2D islands followed by 3D clustering from a critical submonolayer coverage. 相似文献
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Two Er3+/Yb3+ monolithic silica-alumina xerogels doped with different Yb3+ concentrations were prepared by sol–gel route. The samples were thermally treated in air at 950°C for 120 h, and Raman and UV-visible-NIR spectroscopy were used to monitor the degree of densification of the glasses and the residual OH 相似文献
190.
Boris A. Trofimov Boris G. Sukhov Svetlana F. Malysheva Natal’ya A. Belogorlova Anatolii P. Tantsirev Lidiya N. Parshina Ludmila A. Oparina Sergey P. Tunik Nina K. Gusarova 《Tetrahedron letters》2004,45(49):9143-9145
Secondary phosphines react readily with a vinyl ether of diacetone-d-glucose under radical initiation conditions to give, in high yield, anti-Markovnikov adducts, diorganyl{2-[3-O-(1,2:5,6-di-O-isopropylidene)-d-glucofuranosyloxy]ethyl}phosphines, which oxidize almost quantitatively upon reacting with air oxygen or elemental sulfur to form the corresponding optically active phosphine oxides or sulfides. 相似文献