Finding optimal surface sites on heterogeneous catalysts by counting nearest neighbors

TLDR

A good heterogeneous catalyst often relies on a single specific surface site, yet conventional Sabatier‑type activity plots are hard to use for designing new catalysts. The study introduces coordination‑activity plots to predict the geometric structure of optimal active sites. The authors illustrate the method on the oxygen‑reduction reaction on platinum and use it to design highly active Pt(111) sites via three affordable experimental approaches without alloying. The method predicts that Pt(111) sites with the same first‑nearest‑neighbor count as terraces but more second‑nearest neighbors exhibit superior catalytic activity.

Abstract

A good heterogeneous catalyst for a given chemical reaction very often has only one specific type of surface site that is catalytically active. Widespread methodologies such as Sabatier-type activity plots determine optimal adsorption energies to maximize catalytic activity, but these are difficult to use as guidelines to devise new catalysts. We introduce "coordination-activity plots" that predict the geometric structure of optimal active sites. The method is illustrated on the oxygen reduction reaction catalyzed by platinum. Sites with the same number of first-nearest neighbors as (111) terraces but with an increased number of second-nearest neighbors are predicted to have superior catalytic activity. We used this rationale to create highly active sites on platinum (111), without alloying and using three different affordable experimental methods.