scholarly journals Exploring the mineral–water interface: reduction and reaction kinetics of single hematite (α-Fe2O3) nanoparticles

2016 ◽  
Vol 7 (2) ◽  
pp. 1408-1414 ◽  
Author(s):  
K. Shimizu ◽  
K. Tschulik ◽  
R. G. Compton
Keyword(s):  
Reaction Kinetics ◽  
Mineral Water ◽  
Reductive Dissolution ◽  
Particle Impact ◽  
Water Interface ◽  
Fe2o3 Nanoparticles ◽  
Kinetics And Thermodynamics ◽  
Interface Reduction ◽  
Kinetics Of

Here we show that particle impact chronoamperometry allows the quantitative electrochemical characterization of individual mineral nanoparticles with adequate proton concentrations. Through this approach, we extract the kinetics and thermodynamics of the reductive dissolution of single hematite (α-Fe2O3) nanoparticles.

Relationships among structure, reactivity towards thiols and basicity of phenylhydrazonopropanedinitriles

1985 ◽  
Vol 50 (9) ◽  
pp. 2065-2076 ◽  
Author(s):  
Ernest Šturdík ◽  
Marián Antalík ◽  
Pavol Sulo ◽  
Štefan Baláž ◽  
Edita Ďurčová ◽  
...  
Keyword(s):  
Reaction Kinetics ◽  
Rate Constants ◽  
Simple Relation ◽  
Second Order ◽  
Spectrophotometric Investigation ◽  
Hammett Constants ◽  
Similar Dependence ◽  
Kinetics Of ◽  
Derivatives Of

Data required for characterization of reactivity of ortho-, meta-, and para-substituted derivatives by first and second order rate constants were obtained from spectrophotometric investigation of reaction kinetics of phenylhydrazonopropanedinitriles with model thiols. The reactivity has been found to be linearly dependent on Hammett constants of substituents. Similar dependence revealed the basicity characterized by pKa values determined spectrophotometrically. Whilst reactivity and basicity of meta- and para-substituted derivatives is dependent, ortho-substituted derivatives did not obey any simple relation between reactivity and basicity. This finding is important for utilization of ortho-derivatives of phenylhydrazonopropanedinitrile when studying the uncoupling effect of these substances upon oxidative and photosynthetic phosphorylation.

Comparative activity of thrombin on substituted arginine and lysine esters

1965 ◽  
Vol 209 (3) ◽  
pp. 577-583 ◽  
Author(s):  
Sol Sherry ◽  
Norma Alkjaersig ◽  
Anthony P. Fletcher
Keyword(s):  
Amino Acid ◽  
Methyl Ester ◽  
Reaction Kinetics ◽  
Proteolytic Enzymes ◽  
Basic Amino Acid ◽  
Bovine Thrombin ◽  
Bovine Plasma ◽  
Separate Identity ◽  
Kinetics Of

A number of biologically important proteolytic enzymes, particularly those involved in the reactions of blood coagulation and fibrinolysis, have the ability to hydrolyze synthetic esters of the basic amino acids, arginine, and lysine. Though synthetic amino acid esters have been used for the study of the reaction kinetics of these enzymes and for assay purposes, relatively little has been done to characterize these enzymes on the basis of their differing abilities to hydrolyze synthetic substrates. Utilizing a variety of comparably substituted arginine and lysine esters, observations were made on the reaction kinetics of several basic amino acid esterases; significant differences were noted among these enzymes, sufficient to establish their separate identity. Further characterization of the reaction of thrombin with synthetic substrates revealed that this enzyme readily hydrolyzes various substituted lysine esters as well as arginine esters. The highest Vmax was observed for the throm-bin-carbobenzoxy-lysine methyl ester reaction but the greatest affinity was observed with benzoyl-arginine methyl ester. The data also clearly establish enzymatic differences between human and bovine thrombin, and between the latter and bovine plasma thrombokinase.

On-line characterization of the activity and reaction kinetics of immobilized enzyme by high-performance frontal analysis

2000 ◽  
Vol 903 (1-2) ◽  
pp. 77-84 ◽  
Author(s):  
Honghai Jiang ◽  
Hanfa Zou ◽  
Hailin Wang ◽  
Jianyi Ni ◽  
Qiang Zhang ◽  
...  
Keyword(s):  
Reaction Kinetics ◽  
High Performance ◽  
Immobilized Enzyme ◽  
Frontal Analysis ◽  
On Line ◽  
Kinetics Of

Irradiation behavior of pyrolytic silicon carbide

1983 ◽  
Vol 41 ◽  
pp. 72-73
Author(s):  
R. J. Lauf
Keyword(s):  
Silicon Carbide ◽  
Fission Products ◽  
Thermodynamics And Kinetics ◽  
Neutron Fluences ◽  
Fuel Particles ◽  
Sic Coatings ◽  
Irradiation Behavior ◽  
Kinetics Of ◽  
Htgr Fuel

Fuel particles for the High-Temperature Gas-Cooled Reactor (HTGR) contain a layer of pyrolytic silicon carbide to act as a miniature pressure vessel and primary fission product barrier. Optimization of the SiC with respect to fuel performance involves four areas of study: (a) characterization of as-deposited SiC coatings; (b) thermodynamics and kinetics of chemical reactions between SiC and fission products; (c) irradiation behavior of SiC in the absence of fission products; and (d) combined effects of irradiation and fission products. This paper reports the behavior of SiC deposited on inert microspheres and irradiated to fast neutron fluences typical of HTGR fuel at end-of-life.

Impact Of Synthesis Route on the Water Oxidation Kinetics of Hematite Photoanodes

2020 ◽  
Author(s):  
Camilo A. Mesa ◽  
Ludmilla Steier ◽  
Benjamin Moss ◽  
Laia Francàs ◽  
James E. Thorne ◽  
...  
Keyword(s):  
Oxygen Vacancy ◽  
Reaction Kinetics ◽  
Water Oxidation ◽  
Oxidation Kinetics ◽  
Oxidation Reaction ◽  
Charge Accumulation ◽  
Optical Signals ◽  
Current Voltage ◽  
Voltage Performance ◽  
Kinetics Of

<p><i>Operando</i> spectroelectrochemical analysis is used to determine the water oxidation reaction kinetics for hematite photoanodes prepared using four different synthetic procedures. Whilst these photoanodes exhibit very different current / voltage performance, their underlying water oxidation kinetics are found to be almost invariant. Lower photoanode performance was found to correlate with the observation of optical signals indicative of charge accumulation in mid-gap oxygen vacancy states, indicating these states do not contribute directly to water oxidation.</p>

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