Outlining the Scaling-Based and Scaling-Free Optimization of Electrocatalysts

For nearly 15 years, significant efforts have been directed toward the computational design of electrocatalysts for a variety of important reactions. Despite conspicuous discoveries, enhancing electrocatalysts is still a feat rather than a routine task. This could be due to the fact that computational materials design is often guided by heuristic rules. Here we outline a systematic procedure for the optimization of electrocatalysts using two independent parameters: δ, which is restricted by adsorption-energy scaling relations, and ε, which is scaling-free. Taking the prototypical oxygen evolution reaction as a case study, we mathematically show that, contrary to the widespread idea, stabilizing *OOH with respect to *OH is not a universal principle to go beyond the top of the activity volcano. Conversely, the δ−ε optimization lowers the calculated overpotentials in nearly all analyzed cases, suggesting that “electrocatalytic symmetry” is the only general thermodynamic recipe for optimal electrocatalysis. Using δ−ε analyses, screening studies can identify (1) the most promising materials, (2) the problematic reaction intermediates, and (3) the materials’ ease of optimization.