The tube electrode and e.s.r (original) (raw)
Related papers
On convective mass transfer in laminar flow between two parallel electrodes in a rectangular channel
Journal of Electroanalytical Chemistry and Interfacial Electrochemistry
The problem of convective diffusion in steady state laminar flow between two parallel plates is investigated, with different conditions imposed at the wall surfaces. An approach to the analytical solution of the convective diffusion is discussed under different boundary conditions imposed on the equation governing the physical process. A numerical procedure involving the implicit finite difference method to simulate the convective diffusion is indicated as an alternative way to get results for the same problem. The case of two parallel electrodes constituting the channel walls with a mass transfer limited electrochemical reaction is emphasized. A comparison is made between the case of two electrodes, and that for only one electrode at the channel wall, the discussion on the signal to noise ratio for these cases being also included.
Numerical simulation of convective diffusion at a rectangular channel flow electrode
Journal of Electroanalytical Chemistry
The magnitude of the current is numerically computed for a mass transfer limited electrochemical reaction at a plane electrode in a rectangular channel under conditions of steady state, fully developed laminar flow. The procedure is based on the backward implicit finite difference numerical method, applied to solve the differential equation governing convective diffusion. The convergence and error limits inherently present in the procedure are evaluated over a wide range of conditions, and compared with results obtained for the explicit finite difference method and the implicit Crank-Nicolson method. The backward implicit method is highly advantageous for solving problems of the type investigated. Very good agreement is obtained with other experimental and semi-empirical studies over a wide range of operational parameters of the channel electrode.
Convective diffusion with homogeneous and heterogeneous reactions in a tube
The Journal of Physical Chemistry, 1980
Publication costs assisted by Brookhaven National Laboratory A new complete solution for laminar flow with axial diffusion and first-order homogeneous and wall reactions in a tube is presented. The solution is in terms of an eigenfunction series expansion. Effects of axial diffusion, homogeneous reaction, and wall reaction on the concentration field are discussed. Comparison of the simplified results derived from the present analysis by neglecting axial diffusion and wall reaction with those of previous workers shows good agreement. Conditions are established for the necessity of applying the present results to describe the system accurately.
Mass transfer to tubular electrodes. Part 2: CE process
1998
The kinetic equations for an electrochemical process consisting of a homogeneous firstorder chemical reaction followed by electron transfer at the electrode surface are solved numerically, for linear sweep voltammetry under hydrodynamical conditions in a tubular electrode. Models for both the cases involving reversible as well as irreversible electrode charge transfer reaction are investigated. The influence on current-potential voltammograms of the experimentally measurable parameters like the potential scan rate, axial flow rate and chemical equilibrium parameter is examined and depicted graphically.
Analytical Chemistry, 2007
Microband arrays improve the analytical performance and information content of electrochemical detection in flow channel relative to single-electrode configurations. However, exploiting their full advantages requires a detailed understanding of the properties of arrays, which depend on their geometry and on the hydrodynamic regimes established inside the microfluidic channel. This paper investigates the influence of two main operating situations (sequential and coupling regimes) on steady-state amperometric responses of microband arrays performing under laminar flow conditions. Simulations and experimental measurements showed that the resulting properties of the arrays are a function of the number of electrodes and average ratio between gaps and electrode widths, whether the layout of the arrays is regular or not. Since the contribution of each electrode can be finely tailored, this allows the arrays to be designed and adapted to a wide variety of experimental demands.
Analytical Chemistry, 2010
Microband arrays improve the analytical performance and information content of electrochemical detection in flow channel relative to single-electrode configurations. However, exploiting their full advantages requires a detailed understanding of the properties of arrays, which depend on their geometry and on the hydrodynamic regimes established inside the microfluidic channel. This paper investigates the influence of two main operating situations (sequential and coupling regimes) on steady-state amperometric responses of microband arrays performing under laminar flow conditions. Simulations and experimental measurements showed that the resulting properties of the arrays are a function of the number of electrodes and average ratio between gaps and electrode widths, whether the layout of the arrays is regular or not. Since the contribution of each electrode can be finely tailored, this allows the arrays to be designed and adapted to a wide variety of experimental demands.
Analytical Chemistry, 2008
Microband arrays improve the analytical performance and information content of electrochemical detection in flow channel relative to single-electrode configurations. However, exploiting their full advantages requires a detailed understanding of the properties of arrays, which depend on their geometry and on the hydrodynamic regimes established inside the microfluidic channel. This paper investigates the influence of two main operating situations (sequential and coupling regimes) on steady-state amperometric responses of microband arrays performing under laminar flow conditions. Simulations and experimental measurements showed that the resulting properties of the arrays are a function of the number of electrodes and average ratio between gaps and electrode widths, whether the layout of the arrays is regular or not. Since the contribution of each electrode can be finely tailored, this allows the arrays to be designed and adapted to a wide variety of experimental demands.
Mass transfer to tubular electrodes: ECE process
2000
The mathematical model of mass transport for linear sweep voltammetry under hydrodynamic conditions at tubular electrodes has been studied for ECE processes in which an irreversible chemical reaction is coupled between two reversible charge transfer reactions. The resulting boundary value problem is converted into system of two integral equations, which is solved numerically. The effects of axial flow rate, scan rate, potential difference, variation of chemical reaction rate and the effect of the ratio of number of electrons (n 2 /n 1 ) involved in two charge transfer reactions on CV-voltammograms are investigated and shown graphically.
Electroanalysis, 2004
An analytical solution is developed for heterogeneous ECE processes occurring at channel electrode surface for both laminar and turbulent flow. The solution explicitly links the behavior of ECE processes and the parameters. A simple expression of the effective number of electrons transferred, covering all the reaction rate constants and different diffusion coefficients of the reactant A and the intermediate product B, is obtained. Excellent agreement with previous numerical and analytical results is shown. Parametric studies illustrate the effects of diffusion coefficients, hydrodynamic factors and reaction rate constants on the effective number of electrons transferred and the currents.