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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.

Electrochemical conversion of CO(2) into hydrocarbons and oxygenates is envisioned as a promising path toward closing the carbon cycle in modern technology. To date, however, the reaction mechanisms toward the plethora of products are disputed, complicating the search for alternative catalyst materials. To conclusively identify the rate-limiting steps in CO reduction on Cu, we analyzed the mechanisms on the basis of constant-potential density functional theory (DFT) kinetics and experiments at a wide range of pH values (3–13). We find that *CO dimerization is energetically favored as the rate-limiting step toward multicarbon products. This finding is consistent with our experiments, where the reaction rate is nearly unchanged on a standard hydrogen electrode (SHE) potential scale, even under acidic conditions. For methane, both theory and experiments indicate a change in the rate-limiting step with electrolyte pH from the first protonation step under acidic/neutral conditions to a later one under alkaline conditions. We also show, through a detailed analysis of the microkinetics, that a surface combination of *CO and *H is inconsistent with the measured current densities and Tafel slopes. Finally, we discuss the implications of our understanding for future mechanistic studies and catalyst design.

Insights into the mechanism of the catalytic cycle for methanol dehydrogenation catalyzed by a highly active PNP pincer ruthenium complex in methanol solvent are presented, using DFT-based molecular dynamics with an explicit description of the solvent, as well as static DFT calculations using microsolvation models. In contrast to previous results, we find the amido moiety of the catalyst to be permanently protonated under catalytic conditions. Solvent molecules actively participate in crucial reaction steps and significantly affect the reaction barriers when compared to pure gas-phase models, which is a direct result of the enhanced solvent stabilization of methoxide anion intermediates. Further, the calculations reveal that this system does not operate via the commonly assumed Noyori-type outer-sphere metal–ligand cooperative pathway. Our results show the importance of incorporating a molecular description of the solvent to gain a deeper and accurate understanding of the reaction pathways, and stress on the need to involve explicit solvent molecules to model complex catalytic processes in a realistic manner.