(218b) Climbing the Volcano: Active-Site Engineering at the Atomic Scale

Authors: 
In recent years, molecular simulations of catalyst surfaces have yielded considerable insights into how the electronic structure of catalyst materials influences activity. One of the most notable examples is that of the scaling relations, or correlations between adsorption energies of molecules onto surfaces. Using these correlations, models for turnover rates, coverages, and theoretical overpotentials (in the case of electrocatalysis) may be constructed, often yielding "volcano" relationships which may define fundamental limits on the ideal performance of catalysts. Some of the clearest examples of these limits are present in electrocatalysis of earth-ambient molecules into fuels and chemicals, which include reactions like water oxidation and CO2 electroreduction, in which even the most efficient catalysts require significant overpotentials to achieve moderate turnover rates.

In this work, I identify materials for which assumptions of scaling-relation-based models might be strategically broken in order to circumvent fundamental limits on activity. These include bifunctional materials, in which adsorbates interact with multiple sites on a surface and may be selectivity stabilized by distinct moities in alloys and other bulk binary compounds. Electrolytes, interfaces, ligand-functionalized surfaces and confined nanostructures may also achieve a similar selective stabilization or destabilization, being perturbed off of the traditional scaling relation in order to achieve higher activity. Lastly, I describe a high-throughput methodology developed using software infrastructure from the Materials Project which may aid in the more rapid identification of materials which meet these criteria.