Synthesis of highly-active Fe–N–C catalysts for PEMFC with carbide-derived carbons

2018 ◽  
Vol 6 (30) ◽  
pp. 14663-14674 ◽  
Author(s):  
Sander Ratso ◽  
Nastaran Ranjbar Sahraie ◽  
Moulay Tahar Sougrati ◽  
Maike Käärik ◽  
Mati Kook ◽  
...  
Keyword(s):  
Oxygen Reduction ◽  
Electrocatalytic Activity ◽  
Chemical Properties ◽  
Highly Active ◽  
Physico Chemical ◽  
Carbide Derived Carbon

We study the physico-chemical properties and electrocatalytic activity towards oxygen reduction of two Fe–N–C catalysts based on carbide derived carbon.

Facile synthesis of N-doped porous carbon encapsulated bimetallic PdCo as a highly active and durable electrocatalyst for oxygen reduction and ethanol oxidation

2017 ◽  
Vol 5 (22) ◽  
pp. 10876-10884 ◽  
Author(s):  
Zheye Zhang ◽  
Shasha Liu ◽  
Xin Tian ◽  
Juan Wang ◽  
Pei Xu ◽  
...  
Keyword(s):  
Oxygen Reduction ◽  
Porous Carbon ◽  
Electrocatalytic Activity ◽  
Ethanol Oxidation ◽  
Bimetallic Nanoparticles ◽  
Oxidation Reactions ◽  
Facile Synthesis ◽  
Highly Active ◽  
Carbon Nanocapsules

A facile synthesis of ultrafine PdCo bimetallic nanoparticles confined in N-doped porous carbon nanocapsules (PdCo@NPNCs) is presented here. The PdCo@NPNCs exhibit superior electrocatalytic activity and stability towards both the oxygen reduction and ethanol oxidation reactions.

scholarly journals Electrocatalytic hydrogen evolution on the noble metal-free MoS2/carbon nanotube heterostructure: a theoretical study

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Farhad Keivanimehr ◽  
Sajjad Habibzadeh ◽  
Alireza Baghban ◽  
Amin Esmaeili ◽  
Ahmad Mohaddespour ◽  
...  
Keyword(s):  
Hydrogen Evolution ◽  
Noble Metal ◽  
Electrocatalytic Activity ◽  
Density Functional ◽  
Minimum Energy ◽  
Chemical Properties ◽  
Binding Energies ◽  
Functional Theory ◽  
Metal Free ◽  
Physico Chemical

AbstractMolybdenum disulfide (MoS2) is considered as a promising noble-metal-free electrocatalyst for the Hydrogen Evolution Reaction (HER). However, to effectively employ such material in the HER process, the corresponding electrocatalytic activity should be comparable or even higher than that of Pt-based materials. Thus, efforts in structural design of MoS2 electrocatalyst should be taken to enhance the respective physico-chemical properties, particularly, the electronic properties. Indeed, no report has yet appeared about the possibility of an HER electrocatalytic association between the MoS2 and carbon nanotubes (CNT). Hence, this paper investigates the synergistic electrocatalytic activity of MoS2/ CNT heterostructure for HER by Density Functional Theory simulations. The characteristics of the heterostructure, including density of states, binding energies, charge transfer, bandgap structure and minimum-energy path for the HER process were discussed. It was found that regardless of its configuration, CNT is bound to MoS2 with an atomic interlayer gap of 3.37 Å and binding energy of 0.467 eV per carbon atom, suggesting a weak interaction between CNT and MoS2. In addition, the energy barrier of HER process was calculated lower in MoS2/CNT, 0.024 eV, than in the MoS2 monolayer, 0.067 eV. Thus, the study elaborately predicts that the proposed heterostructure improves the intrinsic electrocatalytic activity of MoS2.

scholarly journals Modified lead dioxide for organic wastewater treatment: Physicochemical properties and electrocatalytic activity

2019 ◽  
Vol 84 (2) ◽  
pp. 187-198 ◽  
Author(s):  
Olesia Shmychkova ◽  
Tatiana Luk’yanenko ◽  
Larisa Dmirtikova ◽  
Alexander Velichenko
Keyword(s):  
Wastewater Treatment ◽  
Physicochemical Properties ◽  
Electrochemical Oxidation ◽  
Oxygen Evolution ◽  
Electrocatalytic Activity ◽  
Lead Dioxide ◽  
Chemical Properties ◽  
Destruction Rate ◽  
Physico Chemical ◽  
Pbo2 Anode

An investigation is reported on lead dioxide electrodeposition from methanesulfonate electrolytes additionally containing Ni2+ ions. It is shown that lead dioxide electrodes micromodified by nickel have different physico-chemical properties vs. nonmodified PbO2-anodes that are formed during the deposition. Electrocatalytical reactivity of electrodes involved in comparison to both the oxygen evolution, as well as to the electrooxidation of 2,4- dichlorophenoxyacetic (2,4-D) acid is investigated. Processes of electrochemical oxidation of 2,4-D on various materials occur qualitatively with the same mechanism and differ only in the rate. It is shown that the Ni-PbO2-anode possesses the highest electrocatalytic activity: the destruction rate of 2,4-D on it increases in 1.5 times in comparison with nonmodified lead dioxide. The COD of a 0.4 mM solution of 2,4-D, determined by the dichromate method, is 90.0 mg dm-3 which is 94 % of the theoretical value.

scholarly journals Synthesis, physico-chemical properties of 2-((4-amino-5-(thiophen-2-ylmethyl)-4H-1,2,4-triazol-3-yl)thio)acetohyd-razides

2018 ◽  
pp. 31-36
Author(s):  
A. A. Safonov
Keyword(s):  
Melting Point ◽  
1H Nmr ◽  
Chemical Properties ◽  
Automatic Device ◽  
Spectral Studies ◽  
Liquid Chromatograph ◽  
High Biological Activity ◽  
Mass Spectral ◽  
Highly Active ◽  
Physico Chemical

The value of the class of 1,2,4-triazole derivatives to create a low-toxic and highly active substances is huge. There are a lot of facts about the high biological activity among a number of substances. The 2-((4-amino-5-(thiophen-2-ylmethyl)-4H-1,2,4-triazol-3-yl)thio)acetohydrazides derivatives causes of particular interest in this direction. The aim of the work was to synthesize 2-((4-amino-5-(thiophen-2-ylmethyl)-4H-1,2,4-triazol-3-yl)thio)acetohydrazides and their derivatives, studying of their physico-chemical properties. 2-((4-amino-5-(thiophen-2-ylmethyl)-4H-1,2,4-triazol-3-yl)thio)-N'-R-acetohydrazides were synthesized by of 2-((4-amino-5-(thiophen-2-ylmethyl)-4H-1,2,4-triazol-3-yl)thio)acetohydrazides with aldehydes and ketones in the i-propanol with the addition of hydrochloric acid. The melting point was determined by an automatic device for determining the melting point OptiMelt Stanford Research Systems MPA100 (US). The elemental composition of compounds found in elemental analyzer Elementar Vario L cube (CHNS) (standard ‒ sulfonamides). Chromatography-mass spectral studies conducted on gas-liquid chromatograph Agilent 1260 Infinity HPLC with equipped mass spectrometer Agilent 6120, 1H-NMR-spectra were registered on spectrometer Mercury 400 A series of new 2-((4-amino-5-(thiophen-2-ylmethyl)-4H-1,2,4-triazol-3-yl)thio)-N'-R-acetohydrazides derivatives were synthesized, R-2-chloro-6-fluorobenzylidene, 3-nitrobenzylidene, 4-hydroxybenzylidene, 2-nitrobenzylidene, 2,4-dimethylbenzylidene, 3,5-dimethoxybenzylidene, 3-bromo-4-fluorobenzylidene, 2,3-dimethoxybenzylidene, 2-bromobenzylidene, 2-fluorobenzylidene, 4-(dimethylamino)benzylidene, pyridin-2-ylmethylene, 5-nitrofuran-2-ylmethylene, 4-methoxybenzylidene, 2-hydroxybenzylidene, 4-methoxyphenyl)ethylidene, 1-(thiophen-2-yl)ethylidene. The structure of these compounds was established by modern physico-chemical analysis methods (elemental analysis, 1H-NMR spectroscopy). Individuality was proved by HPLC-MS.

Enhanced electrocatalytic activity of nitrogen-doped olympicene/graphene hybrids for the oxygen reduction reaction

2016 ◽  
Vol 18 (33) ◽  
pp. 22799-22804 ◽  
Author(s):  
Xiuli Hou ◽  
Peng Zhang ◽  
Shuang Li ◽  
Wei Liu
Keyword(s):  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Electrocatalytic Activity ◽  
Reduction Reaction ◽  
Nitrogen Doped ◽  
Co Tolerance ◽  
Highly Active

N-Doped olympicene/graphene hybrids are highly active for ORR and have good CO tolerance.

Decoration of specific sites on freeze-fractured membranes

1978 ◽  
Vol 36 (2) ◽  
pp. 140-141
Author(s):  
H. Gross ◽  
H. Moor
Keyword(s):  
Pure Water ◽  
Freeze Fracture ◽  
Chemical Properties ◽  
Surface Forces ◽  
Sulfate Pentahydrate ◽  
Copper Sulfate Pentahydrate ◽  
Physico Chemical ◽  
Water Of Hydration ◽  
Small Container ◽  
Binding Forces

Fracturing under ultrahigh vacuum (UHV, p ≤ 10-9 Torr) produces membrane fracture faces devoid of contamination. Such clean surfaces are a prerequisite foe studies of interactions between condensing molecules is possible and surface forces are unequally distributed, the condensate will accumulate at places with high binding forces; crystallites will arise which may be useful a probes for surface sites with specific physico-chemical properties. Specific “decoration” with crystallites can be achieved nby exposing membrane fracture faces to water vopour. A device was developed which enables the production of pure water vapour and the controlled variation of its partial pressure in an UHV freeze-fracture apparatus (Fig.1a). Under vaccum (≤ 10-3 Torr), small container filled with copper-sulfate-pentahydrate is heated with a heating coil, with the temperature controlled by means of a thermocouple. The water of hydration thereby released enters a storage vessel.

Physico-Chemical Properties of Recombinant Desulphatohirudin

1990 ◽  
Vol 63 (03) ◽  
pp. 499-504 ◽  
Author(s):  
A Electricwala ◽  
L Irons ◽  
R Wait ◽  
R J G Carr ◽  
R J Ling ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Gel Filtration ◽  
Chemical Properties ◽  
Alpha Helix ◽  
Apparent Molecular Weight ◽  
Correlation Spectroscopy ◽  
Nmr Studies ◽  
Recombinant Hirudin ◽  
Physico Chemical ◽  
Recombinant Molecule

SummaryPhysico-chemical properties of recombinant desulphatohirudin expressed in yeast (CIBA GEIGY code No. CGP 39393) were reinvestigated. As previously reported for natural hirudin, the recombinant molecule exhibited abnormal behaviour by gel filtration with an apparent molecular weight greater than that based on the primary structure. However, molecular weight estimation by SDS gel electrophoresis, FAB-mass spectrometry and Photon Correlation Spectroscopy were in agreement with the theoretical molecular weight, with little suggestion of dimer or aggregate formation. Circular dichroism studies of the recombinant molecule show similar spectra at different pH values but are markedly different from that reported by Konno et al. (13) for a natural hirudin-variant. Our CD studies indicate the presence of about 60% beta sheet and the absence of alpha helix in the secondary structure of recombinant hirudin, in agreement with the conformation determined by NMR studies (17)

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