scholarly journals Theoretical Insights into Effect of Surface Composition of Pt-Ru Bimetallic Catalysts on CH3OH Oxidation: Mechanistic Considerations

Author(s):  
Lihui Ou

Abstract A deeper mechanistic understanding on CH3OH oxidation on Pt-Ru alloys with different Ru surface compositions is provided by DFT-based theoretical studies in this paper. The present results show that alloying and surface compositions of Ru can change CH3OH oxidation pathway and activity. The optimal surface composition of Ru is speculated to be ca. 50% since the higher Ru surface composition can lead to formation of carbonaceous species that can poison surface. Our present calculated Ru surface composition of ca. 50% exhibits excellent consistency with experimental studies. The origin of enhanced catalytic activity of Pt-Ru alloys is determined. The significantly decreased surface work functions after alloying suggest more electrons are transferred into adsorbates. The calculated lower electrode potentials after alloying imply that lower overpotentials are required for CH3OH oxidation. The excellent inconsistency with experimental study on decreased onset potentials after alloying further confirms accuracy of our present calculated results.

Author(s):  
Alexey V. Kavokin ◽  
Jeremy J. Baumberg ◽  
Guillaume Malpuech ◽  
Fabrice P. Laussy

This chapter presents experimental studies performed on planar semiconductor microcavities in the strong-coupling regime. The first section reviews linear experiments performed in the 1990s that evidence the linear optical properties of cavity exciton-polaritons. The chapter is then focused on experimental and theoretical studies of resonantly excited microcavity emission. We mainly describe experimental configuations in which stimulated scattering was observed due to formation of a dynamical condensate of polaritons. Pump-probe and cw experiments are described in addition. Dressing of the polariton dispersion and bistability of the polariton system due to inter-condensate interactions are discussed. The semiclassical and the quantum theories of these effects are presented and their results analysed. The potential for realization of devices is also discussed.


2015 ◽  
Vol 1 (3) ◽  
pp. 213-220 ◽  
Author(s):  
Wei Geng ◽  
Chuan-Jia Tong ◽  
Zhen-Kun Tang ◽  
ChiYung Yam ◽  
Yan-Ning Zhang ◽  
...  

Author(s):  
S.V. Matsenko ◽  
◽  
V.M. Minko ◽  
A.A. Koshelev ◽  
V.Yu. Piven ◽  
...  

Violation of industrial safety rules during the operation of offshore facilities for the production, storage and transportation of the hydrocarbon raw materials leads in the most cases to pollution of the marine environment with oil and its components. The works on localization and elimination of such pollution are carried out with the help of vessels of the technical support fleet and booms. When developing oil spill response plans at such facilities, a calculated determination of the technical characteristics of vessels and booms is required that are sufficient to carry out the planned activities. The basic design principles for determining the towing capacity of the technical fleet vessels involved in the localization and elimination of oil and oil product spills by trawling methods are given in the article. The calculation is based on theoretical studies performed by the authors of the physical processes occurring during the movement of objects of a mobile trawling order in the sea area. The results obtained during the course of theoretical studies were confirmed by the experimental studies carried out by the authors personally using the real pieces of equipment in the actual development of tasks for training spill containment by trawling. As a result, the empirical dependencies were obtained and experimentally confirmed, which can be used to calculate technical characteristics of the ships as part of the mobile orders and anchor systems as part of stationary orders intended for the localization and elimination of oil pollution. These results can be used, among other things, for the calculated substantiation of the technical characteristics of the technical fleet vessels designed to ensure safety of the offshore facilities for production, storage, and transportation of the hydrocarbon raw materials.


RSC Advances ◽  
2018 ◽  
Vol 8 (31) ◽  
pp. 17346-17356 ◽  
Author(s):  
Mohammad Zabihi ◽  
Nasser Babajani

This study reveals the simultaneous deep oxidation of toluene and cyclohexane over optimal supported bimetallic catalysts over almond shell based activated carbon.


2018 ◽  
Vol 12 (5) ◽  
pp. 20-24
Author(s):  
D. Z. Yeskhozhin ◽  
S. O. Nukeshev ◽  
G. I. Lichman ◽  
Ye. S. Akhmetov ◽  
K. D. Yeskhozhin

Livestock products are the most important component of the actual total volume of farm produce. A reliable fodder base is required to increase their quantity and quality. The most part of the natural forage lands of the Republic of Kazakhstan is located in areas with insufficient water availability and low soil productivity. When they are used intensively, they are thinned and degraded. Their restoration and improving is possible if effective technologies and technical means are effected. However, the existing methods for improving and restoring forage lands and the technical means for their implementation are not adapted to the natural­climatic and agrobiological features of the zone of Central and Northern Kazakhstan, which feature insufficient moisture supply and low productivity.The main indicator of the effectiveness of the use of fodder crop seeds is their uniform distribution in the soil. However, most of them, due to their poor flowability, form dome structures of different sizes in front of seeding openings, which hinder the seeding process. To increase the flowability of such seeds, they are mixed with sand, sawdust, fertilizer and other materials. However, during the operation of seeders, the mixture is stratified according to its specific gravity. (The research purpose) is to develop a lobe­type agitator, which prevents the formation of a dome over seed holes. (Materials and methods) Theoretical studies have been carried out using the methods of classical and applied mechanics, as well as special sections of higher mathematics. (Results and discussion) The authors have experimentally confirmed the main parameters of the agitator and its resistance to movement in a seed medium. Experimental studies have been carried out on the basis of GOST 31345­2007. The studies have confirmed that a four­lobe agitator with an external radius of 0.06 m and an inclination angle to the plane of rotation 20°, mounted on the fertilizer drill SZS­2.0, has shown a total resistance of 3,042 kg with a design value of 2.925 kg. (Conclusions) The obtained results can be offered to the designers and developers of machines of the considered type when calculating and designing their working elements.


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