Models for mediated reactions at film modified electrodes: controlled electrode potential

Heterogeneous Molecular Catalysis of Electrochemical Reactions: Volcano Plots and Catalytic Tafel Plots

“…Application of this “Sabatier principle” thus predicts the existence of a maximuma “volcano”on the plot of the exchange current vs the adsorption free energy of the intermediate within a family of electrocatalysts of a given reaction. These notions had been put forward as early as the late 1950s, , but they are still the subject of active attention and debate at the present time. − Their application to homogeneous molecular catalysis is quite recent, and in the transposition to molecular film catalysis, we have to take into account the various modes of the coupling between transport of reactants and charge and catalytic reactions. − In order to focus on the possible occurrence of volcano plots in the context of molecular film catalysis, we consider conditions in which the catalytic reaction is the rate-determining factor at the exclusion of charge and reactant transport (the film behaves as a monolayer or as a set of identically behaving monolayers). Within this framework, we will first analyze a simple molecular catalysis one-electron–one-step reaction scheme so as to get down to the nitty-gritty of the appearance or nonappearance of such volcano plots.…”

Conductive Mesoporous Catalytic Films. Current Distortion and Performance Degradation by Dual-Phase Ohmic Drop Effects. Analysis and Remedies

“…The model we use is the result of an averaging of the local structural peculiarities. It is a powerful tool which allows the representation and treatment of many practical cases that may differ in their details, as in the case of supercapacitors , as well as of catalytic films. − Detailed structural features can obviously not be derived from current–potential responses, in cyclic voltammetry as well as with other electrochemical techniques. The most efficient approach of these mesoporous films proceeds actually in a reverse way: gross structural traits are used to build an averaged approximate model that will allow the analysis and characterization of the faradaic and nonfaradaic characteristics of the system, which are what we need for generator or electrolyzer applications and benchmarking.…”

Analysis of electrocatalytic metal-organic frameworks

“…How the overall current-potential response depends on these three processes will result from the solution to a system of partial differential equations, each consisting of Fick's second law (to account for substrate diffusion or electron-hopping/ diffusion) and a kinetic term resulting from the coupled catalytic reaction. Such kinetic models have been developed and well-studied for redox-polymer films [185][186][187][188][189] and bioelectrocatalytic films [190,191], but have yet to be applied to MOF-catalyzed electrochemical reactions. Costentin and Savéant have recently extended the analysis of the current-potential response of porous (multi-layer) electrocatalytic films from steady-state techniques (rotating-disk electrode voltammetry) to cyclic voltammetry [167,182,192].…”