The impact of overpotential on the enthalpy of activation and pre-exponential factor of electrochemical redox reactions

Abstract

The energetics of the electrochemical, electro-inhibiting and electrocatalytic reactions as a function of overpotential.

Influence of Nitrogen Doping into Carbon on the Activation Barrier of ORR in Alkaline Medium: An Investigation Based on Eyring Analysis

“…Eyring analysis (eq ) is used to account for the change in enthalpy of activation (Δ H # ) and entropy of activation (Δ S # ) in the activated complex. − k T = κ k B h exp true( − normalΔ G # R T true) Here k is the reaction rate constant, κ is the transmission coefficient, k B and h are the Boltzmann and Planck constants, Δ G # is the Gibbs free energy of activation, R is the gas constant, and T is the temperature.…”

Relationship between the electron-transfer coefficients of the oxygen reduction reaction estimated from the Gibbs free energy of activation and the Butler–Volmer equation

“…34 At times, however, degradation of the electrode material, and precipitation of the adsorbing species can impede the reaction rates. 35…”

“…This deviation in the α H value was attributed to blocking of the active sites on the electrode surface by precipitates and/or adsorbates. 35…”

“…34 At times, however, degradation of the electrode material, and precipitation of the adsorbing species can impede the reaction rates. 35 The electrochemical reaction rate is usually explained using Butler-Volmer (B-V) theory, the Tafel equation at high overpotentials (Z), and the Arrhenius equation. [36][37][38] Our understanding of correction of the kinetic current for the surface coverage (y), interaction parameters, and free energy of adsorption has improved over time.…”

“…This deviation in the a H value was attributed to blocking of the active sites on the electrode surface by precipitates and/or adsorbates. 35 In the present investigation, our primary interest is to test the Z dependence of DH # for the oxygen reduction reaction (ORR) so that a H can be estimated from qDH # /qZ. The a values estimated from the Tafel slope are different, and the origin of such difference is investigated and a theoretical background is provided.…”