The Experts below are selected from a list of 117384 Experts worldwide ranked by ideXlab platform
Jaeyoung Lee - One of the best experts on this subject based on the ideXlab platform.
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Effect of transition metal induced pore structure on oxygen reduction Reaction of electrospun fibrous carbon
Catalysis Today, 2016Co-Authors: Dongyoon Shin, Myounghoon Choun, Jaeyoung LeeAbstract:Abstract Although significant progress has been made in the development of carbon-based oxygen reduction Reaction catalysts in alkaline media, it is still needed to do relevant investigation of experimental factors that could influence the electrocatalytic activity of alternative electrocatalysts. In this study, we report the effect of transition metals placed into/onto nitrogen doped carbon nanofibers on the ORR performance. We demonstrated various behaviors of oxygen reduction Reaction Reactivity depending on embedded transition metals. Detailed physicochemical analysis showed that different surface area and pore structure were formed according to a number of metals and these structural varieties were resulted from difference in catalytic graphitization phenomenon.
Zhao Jiang - One of the best experts on this subject based on the ideXlab platform.
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structure evolution and gasification characteristic analysis on co pyrolysis char from lignocellulosic biomass and two ranks of coal effect of wheat straw
Fuel, 2019Co-Authors: Zhiqiang Wu, Zhao JiangAbstract:Abstract Evolution of co-pyrolysis char structure significantly influences its Reaction Reactivity. To explore the effect of structure on gasification characteristics of char, two ranks of coal, including anthracite coal (AC) and bituminous coal (BC) were introduced to the pyrolysis of wheat straw (WS). Microlithic and pore textures of char were examined by X-ray diffraction and specific surface area analyzer. Based on fractal theory and deconvolution method, quantitatively analysis from the effect of WS on co-pyrolysis char structure was obtained. Kinetic parameters of gasification were solved via the non-isothermal method and thermogravimetric analysis under CO 2 atmosphere. The results showed that WS promoted the specific surface area of both BCWS char and ACWS char, but the promotion on the pore structure, including average pore size, was different. WS inhibited the ordering and uniformity of micro-scale structure of BCWS and ACWS char. Positive synergy from kinetic parameters during gasification of co-pyrolysis char was observed. Exponential relationship from microcrystalline structure parameter and gasification Reactivity was found.
Alain Sellier - One of the best experts on this subject based on the ideXlab platform.
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A three-step method for the recovery of aggregates from concrete
Construction and Building Materials, 2013Co-Authors: Xiao Xiao Gao, Martin Cyr, Stéphane Multon, Alain SellierAbstract:This work aims to develop a method to recover aggregates from existing concrete in the framework of evaluating the ASR (Alkali-Silica Reaction) Reactivity of these recovered aggregates. To achieve its purpose, the method should guarantee recovery of the maximum amount of all sizes of aggregates and should dissolve the hydrated cement as completely as possible, without altering the composition of the aggregate. A three-step methodology is proposed: rough crushing of the concrete, separation of cement paste from aggregates through a thermal treatment, and dissolution of the remaining attached mortar by chemical attack. This method was tested on concretes cast with known amounts of aggregates. The recovered aggregates were comparable to natural aggregates regarding their particle size distribution. An efficiency of 90-92% was obtained on quartzite and siliceous limestone, with very high recovery rates for particles larger than 1 mm. (C) 2013 Elsevier Ltd. All rights reserved.
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A three-step method for the recovery of aggregates from concrete
Construction and Building Materials, 2013Co-Authors: Xiao Xiao Gao, Martin Cyr, Stéphane Multon, Alain SellierAbstract:Abstract This work aims to develop a method to recover aggregates from existing concrete in the framework of evaluating the ASR (Alkali–Silica Reaction) Reactivity of these recovered aggregates. To achieve its purpose, the method should guarantee recovery of the maximum amount of all sizes of aggregates and should dissolve the hydrated cement as completely as possible, without altering the composition of the aggregate. A three-step methodology is proposed: rough crushing of the concrete, separation of cement paste from aggregates through a thermal treatment, and dissolution of the remaining attached mortar by chemical attack. This method was tested on concretes cast with known amounts of aggregates. The recovered aggregates were comparable to natural aggregates regarding their particle size distribution. An efficiency of 90–92% was obtained on quartzite and siliceous limestone, with very high recovery rates for particles larger than 1 mm.
Sungjin Park - One of the best experts on this subject based on the ideXlab platform.
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Coordination Chemistry of [Co(acac)2 ] with N-Doped Graphene: Implications for Oxygen Reduction Reaction Reactivity of Organometallic Co-O4 -N Species.
Angewandte Chemie (International ed. in English), 2015Co-Authors: Jongwoo Han, Yeonjun Shim, Min Choi, Noejung Park, Sang Hoon Joo, Sungjin ParkAbstract:Hybridization of organometallic complexes with graphene-based materials can give rise to enhanced catalytic performance. Understanding the chemical structures within hybrid materials is of primary importance. In this work, archetypical hybrid materials are synthesized by the Reaction of an organometallic complex, [Co(II) (acac)2 ] (acac=acetylacetonate), with N-doped graphene-based materials at room temperature. Experimental characterization of the hybrid materials and theoretical calculations reveal that the organometallic cobalt-containing species is coordinated to heterocyclic groups in N-doped graphene as well as to its parental acac ligands. The hybrid material shows high electrocatalytic activity for the oxygen reduction Reaction (ORR) in alkaline media, and superior durability and methanol tolerance to a Pt/C catalyst. Based on the chemical structures and ORR experiments, the catalytically active species is identified as a Co-O4 -N structure.
Dongyoon Shin - One of the best experts on this subject based on the ideXlab platform.
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Effect of transition metal induced pore structure on oxygen reduction Reaction of electrospun fibrous carbon
Catalysis Today, 2016Co-Authors: Dongyoon Shin, Myounghoon Choun, Jaeyoung LeeAbstract:Abstract Although significant progress has been made in the development of carbon-based oxygen reduction Reaction catalysts in alkaline media, it is still needed to do relevant investigation of experimental factors that could influence the electrocatalytic activity of alternative electrocatalysts. In this study, we report the effect of transition metals placed into/onto nitrogen doped carbon nanofibers on the ORR performance. We demonstrated various behaviors of oxygen reduction Reaction Reactivity depending on embedded transition metals. Detailed physicochemical analysis showed that different surface area and pore structure were formed according to a number of metals and these structural varieties were resulted from difference in catalytic graphitization phenomenon.
