Realistic Cyclic Voltammograms from <i>Ab Initio</i> Simulations in Alkaline and Acidic Electrolytes
Jan Rossmeisl, Kim Degn Jensen, Amanda Schramm Petersen, Logi Arnarson, Alexander Bagger, Marı́a Escudero-Escribano
Abstract
Cyclic voltammograms are key to much of the accumulated understanding of the nature of electrochemical interfaces; however, they provide no direct information on the atomic structure of the interface. Herein, we present a method allowing for the direct coupling of ab initio simulations to experiments and vice versa. The methodology proposed is based on the use of the generalized computational hydrogen electrode, which herein has been further developed to account for counterions. The well-studied Pt(111) interface has been investigated in acidic and alkaline media. This has been done both experimentally and computationally, taking into account effects from pH, potential, and ionic strength. Direct comparison between simulations and experiments reveals that the differences between cyclic voltammograms carried out in acidic and alkaline media mainly originate from cation adsorption in alkaline electrolytes. Through the presented methodology, it is possible to obtain a quantitative agreement between experiments and simulations. This paves the way for increasingly realistic representations of the electrochemical interface by simulations and consequently for a deeper understanding on the atomic level of measured cyclic voltammograms.