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In electrocatalysis, the rate of a reaction as a function of applied potential is governed by the Tafel equation, which depends on two parameters: the Tafel slope and the exchange current density (i0). However, current methods to determine these parameters involve subjective removal of data due to the convoluted effects of mass transfer and competitive surface or bulk reactions, resulting in unquantifiable uncertainty. To overcome this challenge, we couple covariance matrix adaptation with a continuum model of CO2 reduction (CO2R) that explicitly deconvolutes non-kinetic effects to extract kinetic parameters associated with 26 literature datasets of CO2R over Ag and Sn catalysts. The fitted kinetic parameters do not converge to a unique set of values, and the Tafel slope and i0 possess an apparent correlation, which we suggest is a consequence of variations in catalyst preparation methods. This work facilitates rigorous benchmarking of electrocatalysts in systems where mass transfer is relevant.

In this manuscript, we examine the role of image charge effects on the electrostatic potential fluctuations experienced by ionic species in the vicinity of an electrode surface. We combine simulation and theory to quantify these fluctuations and how they vary with distance from the electrode surface. We observe that the potential distribution narrows significantly for species within a few electrolyte screening lengths of the electrode. We attribute this narrowing to the effects of image charge fluctuations originating from the polarization response of the electrode. We show that the physical consequences of these image charge effects can be captured in the context of a simple analytical field theory with anti-symmetric boundary conditions. We contextualize these results by discussing their implications for rates of Marcus-like outer-sphere interfacial electron transfer. [ABSTRACT FROM AUTHOR]