Atomistic modeling of electrocatalysis: Are we there yet?

Electrified interfaces play a prime role in energy technologies, from batteries and capacitors to heterogeneous electrocatalysis. The atomistic understanding and modeling of these interfaces is challenging due to the structural complexity and the presence of the electrochemical potential. Including the potential explicitly in the quantum mechanical simulations is equivalent to simulating systems with a surface charge. For realistic relationships between the potential and the surface charge (i.e., the capacity), the solvent and counter charge need to be considered. The solvent and electrolyte description are limited by the computational power: either molecules or ions are included explicitly or implicit solvent and electrolyte descriptions are adopted. The first option is limited by the phase‐space sampling that is at least 10 times too small to reach convergence, while the second is missing a realistic structuring of the interface. Both approaches suffer from a lack of validation against directly comparable experimental data. Furthermore, the limitations of density functional theory in terms of accuracy are critical for these metal/liquid interfaces. Nevertheless, the atomistic insight in electrocatalytic interfaces allows insights with unprecedented details. The joint theoretical and experimental efforts to design non‐noble hydrogen evolution catalysts are discussed as an example for the success of theory to spur and accelerate experimental discoveries. This article is categorized under: Structure and Mechanism > Reaction Mechanisms and Catalysis Electronic Structure Theory > Density Functional Theory Atomistic modeling and understanding of electrified interfaces is challenges and requires a panoply of complementary techniques, from density functional theory to molecular mechanics and continuum theorieands up to meso‐scale models for mass‐transfer.