| 1 | Electrochemical top-down synthesis of C-supported Pt nanoparticles with controllable shape and size:Mechanistic insights and application显示文摘In this work,we demonstrate the power of a simple top-down electrochemical erosion approach to obtain Pt nanoparticle with controlled shapes and sizes(in the range from-2 to-10 nm).Carbon supported nanoparticles with narrow size distributions have been synthesized by applying an alternating voltage to macroscopic bulk platinum structures,such as disks or wires.Without using any surfactants,the size and shape of the particles can be changed by adjusting simple parameters such as the applied potential,frequency and electrolyte composition.For instance,application of a sinusoidal AC voltage with lower frequencies results in cubic nanoparticles;whereas higher frequencies lead to predominantly spherical nanoparticles.On the other hand,the amplitude of the,sinusoidal signal was found to affect the particle size;the lower the amplitude of the applied AC signal,the smaller the resulting particle size.Pt/C catalysts prepared by this approach showed 0.76 A/mg mass activity towards the oxygen reduction reaction which is-2 times higher than the state-of-the-art commercial Pt/C catalyst(0.42 A/mg)from Tanaka.In addition to this,we discussed the mechanistic insights about the nanoparticle formation pathways. | Batyr Garlyyev Sebastian Watzele Johannes Fichtner Jan Michalicka Alexander Schokel Anatoliy Senyshyn Andrea Perego Dingjie Pan Hany A.El-Sayed Jan M.Macak Plamen Atanassov Iryna V.Zenyuk Aliaksandr S.Bandarenka | 2021 | Nano Research2021，14，8： | 2 |
| 5 | Cool Sooting Flames of Hydrocarbons显示文摘This paper presents the study of polycyclic aromatic hydrocarbons (PAH) and paramagnetism of soot particles sampled from cool sooting flames of methane and propane in a separately-heated two-sectional reactor under atmospheric pressure at the reactor temperatures of 670-1170 K. The temperature profiles of the flames were studied. The sampling was carred out with a quarts sampler and the samples were frozen with liquid nitrogen. A number of polyaromatic hydrocarbons such as pyrene. fluoranthene, coronene, anthanthrene, 1,1 2-benzperylene, were identified by spectroscopic methods in the extract of soot. The processes of soot formation at methane- oxygen mixture combustion in the electric field with applied potential changed from 0 to 2,2 kV at different polarity of electrodes have been investigated. It has been stated that at the electrical field application, an increase in soot particle sizes and soot yield occurs; besides, at the application of the field, speeding up the positively charged particles, the interplanar distance decreases. On the basis of investigation of soot particles paramagnetism, it was shown that initially soot particles have high carcinogetic activity and pollute the environment owing to a rapid decrease of the number of these radical centers. The reduction of the radical concentration is connected with radical recombination on soot. | Z.A. MANSUROV Kazakh State National University, Karasai Batyr str., 95, Almaty, 480012, Kazakhstan | 2001 | Journal of Thermal Science2001，10，3： | 0 |
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