Study On The Distribution Of Current Density Of Gas Diffusion Electrode

The gas diffusion electrode is a kind of porous media, gas diffusion through the porousmedium to the solid-liquid interface electrochemical reaction. First through the pore gasreach the liquid surface, follow the diffusion equation of diffusion to the solid-liquid interface reaction in liquids. We focus on and not electrochemical reaction process, but mainly because of the influence of mass transfer on the reaction results, here we focus on is the current density, and also is the reaction after the model of the electrode current density distribution. Gas diffusion electrode can be abstracted into a variety of mathematical model, this paper mainly studies the gas diffusion electrode in a model-hole electrode model, pay attention to the distribution of the current density. The existing results in an extreme condition is assumed infinite reaction speed of the solid-liquid interface, gives the hole electrode current density distribution. This article is for general conditions, including reaction rate in all. First of all, the definition of a mass transfer velocity of mass transfer characterization of the biggest, then the response speed equal to, or greater than, less than a maximum mass transfer velocity were calculated given the current density distribution, and the current density distribution results is analysed. Found that when the reaction speed is equal to or larger than the maximum velocity of mass transfer and the factors affecting the distribution of current density for mass transfer. It was also at this time the current density distribution not with the change of reaction speed change; and reaction speed is less than a maximum mass transfer rate, factors that affect the results of the reaction is the reaction rate, current density changed with reaction rate gradually change distribution. And when the reaction speed is greater than the maximum velocity of mass transfer reaction showed focus on the trend, there is also a concentrated area, three phase AC near the boundary of a zone, most of the reactions are concentrated in the band. At the end of this paper, the relevant research prospects prospect, put forward problem is possibly involved in the further study of this paper does not consider the dissolution rate.This paper mainly includes:1. Introduce the background, introduced in this paper, the gas diffusion electrode model-hole electrode model, put forward the current density distribution 2. Electrode model of liquid phase mass transfer process are expounded, and the internal electrode, the mass transfer process is directly related to the current density distribution. Therefore, the mass transfer process is understanding and study of current density distribution3. Introduction in the current ideal conditions (reaction speed infinite) the current density distribution and the existing research results4. General current conditions (reaction rate non infinite), to the reaction rate as the variable, then the reaction velocity is equal to, greater than and less than the maximum mass transfer rate of current density distribution and the result analysis5. Use the conclusions drawn from this study, The theoretical current limit of the small hole electrode is calculated, and compare with the actual current, Point out the differences and give explanations.6. The main conclusions and Prospect of this article...