Current log-transform vs reactant concentration as a tool for chemical reaction order and electrochemical mechanisms determination—I. General theory in steady-state voltammetry and application to electro-oxidation of thianthrene in presence of water

1982 ◽  
Vol 27 (11) ◽  
pp. 1565-1583 ◽  
Author(s):  
E. Vieil ◽  
M. Maurey-Mey ◽  
G. Cauquis
Keyword(s):  
Steady State ◽  
General Theory ◽  
Chemical Reaction ◽  
Reaction Order ◽  
Reactant Concentration ◽  
Electro Oxidation

scholarly journals Qualitative analysis of an autocatalytic chemical reaction model with decay

2014 ◽  
Vol 144 (2) ◽  
pp. 427-446 ◽  
Author(s):  
Jun Zhou ◽  
Junping Shi
Keyword(s):  
Steady State ◽  
Chemical Reaction ◽  
Reaction Diffusion ◽  
Steady State Solution ◽  
Reaction Model ◽  
Existence Of A Solution ◽  
Positive Steady State ◽  
Chemical Reaction Model ◽  
The One ◽  
Necessary And Sufficient

In this paper, we revisit a reaction—diffusion autocatalytic chemical reaction model with decay. For higher-order reactions, we prove that the system possesses at least two positive steady-state solutions; hence, it has bistable dynamics similar to the system without decay. For the linear reaction, we determine the necessary and sufficient condition to ensure the existence of a solution. Moreover, in the one-dimensional case, we prove that the positive steady-state solution is unique. Our results demonstrate the drastic difference in dynamics caused by the order of chemical reactions.

scholarly journals Thermodynamic Driving Forces and Chemical Reaction Fluxes; Reflections on the Steady State

Molecules ◽  
2020 ◽  
Vol 25 (3) ◽  
pp. 699 ◽  
Author(s):  
Miloslav Pekař
Keyword(s):  
Steady State ◽  
Chemical Reaction ◽  
Driving Force ◽  
Driving Forces ◽  
Point Of View ◽  
Fluid Mixtures ◽  
Similar Work ◽  
Chemical Potentials ◽  
Thermodynamic Driving Force ◽  
Reacting Systems

Molar balances of continuous and batch reacting systems with a simple reaction are analyzed from the point of view of finding relationships between the thermodynamic driving force and the chemical reaction rate. Special attention is focused on the steady state, which has been the core subject of previous similar work. It is argued that such relationships should also contain, besides the thermodynamic driving force, a kinetic factor, and are of a specific form for a specific reacting system. More general analysis is provided by means of the non-equilibrium thermodynamics of linear fluid mixtures. Then, the driving force can be expressed either in the Gibbs energy (affinity) form or on the basis of chemical potentials. The relationships can be generally interpreted in terms of force, resistance and flux.

scholarly journals The Role Of Chemical Reaction In Waste-Form Performance

1987 ◽  
Vol 112 ◽  
Author(s):  
P. L. Chambré ◽  
C. H. Kang ◽  
W. W.-L. Lee ◽  
T. H. Pigford
Keyword(s):  
Mass Transfer ◽  
Steady State ◽  
Dissolution Rate ◽  
Chemical Reaction ◽  
Borosilicate Glass ◽  
Reaction Rate ◽  
Waste Form ◽  
Spent Fuel ◽  
Wide Range ◽  
Chemical Reaction Rate

AbstractThe dissolution rate of waste solids in a geologic repository is a complex function of waste form geometry, chemical reaction rate, exterior flow field, and chemical environment. We present here an analysis to determine the steady-state mass transfer rate, over the entire range of flow conditions relevant to geologic disposal of nuclear waste. The equations for steady-state mass transfer with a chemical-reaction-rate boundary condition are solved by three different mathematical techniques which supplement each other. This theory is illustrated with laboratory leach data for borosilicate-glass and a spherical spent-fuel waste form under typical repository conditions. For borosilicate glass waste in the temperature range of 57°C to 250°C, dissolution rate in a repository is determined for a wide range of chemical reaction rates and for Peclet numbers from zero to well over 100, far beyond any Peclet values expected in a repository. Spent-fuel dissolution in a repository is also investigated, based on the limited leach data now available.

Microwave Synthesis and Characterization of Nanoscale Lanthanum Cobaltite

2012 ◽  
Vol 476-478 ◽  
pp. 1322-1326
Author(s):  
Xiao Yu Jiang ◽  
Jin Chen ◽  
Wen Zhe Chen
Keyword(s):  
Cyclic Voltammetry ◽  
Steady State ◽  
Microwave Irradiation ◽  
Reaction Order ◽  
Synthesis And Characterization ◽  
Cyclic Voltammogram ◽  
Lanthanum Cobaltite ◽  
Bet Analysis ◽  
Perovskite Type

Nanoscale lanthanum cobaltite with perovskite-type was successfully synthesized by microwave irradiation directly and was characterized by XRD, SEM, XPS and BET analysis. The results show that the size of particle was 18 nm averagely, the surface area to be 31.0 m2 g−1. The electrochemical properties were studied by cyclic voltammetry and steady state polarization. The cyclic voltammogram between 0 and 0.55 V exhibited two pairs of redox peaks prior to the onset of O2 evolution in 1 mol dm−3 KOH. The Tafel slope and the reaction order with respect to concentration of OH− were found to be 60 mV decade−1 and ca. 1, respectively.

General theory of steady-state voltammetry

1993 ◽  
Vol 347 (1-2) ◽  
pp. 49-91 ◽  
Author(s):  
Jan C. Myland ◽  
Keith B. Oldham
Keyword(s):  
Steady State ◽  
General Theory

scholarly journals Thermally prepared Ti/RhOx electrodes: II H2 evolution in acid solution

2002 ◽  
Vol 56 (6) ◽  
pp. 231-237 ◽  
Author(s):  
Mario Campari ◽  
Ana Tavares ◽  
Sergio Trasatti
Keyword(s):  
Thermal Decomposition ◽  
Cyclic Voltammetry ◽  
Steady State ◽  
Reaction Mechanism ◽  
Acid Solution ◽  
Reaction Order ◽  
H2so4 Solution ◽  
H2 Evolution ◽  
Final Settlement ◽  
Fractional Reaction

Ti/RhOx electrodes were prepared at 400-600?C by thermal decomposition of Rh chloride. Oxide layers were studied by SEM, cyclic voltammetry and steady-state E-j curves In 0.5 mol dm-3 H2SO4 solution. Voltammetric charge exhibits a maximum at 430?C with fresh electrodes which shifts to 470?C after use for H2 evolution. H2 discharge first produces a decrease in voltammetric charge, then an activation with final settlement to a constant behaviour for "aged" electrodes. H2 evolution on stable RhOx surfaces takes place with 40 mV Tafel slope and a reaction order of 2.5. The fractional reaction order indicates that the surface response to pH is that typical of oxides even for "aged" electrodes. A reaction mechanism is proposed.

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