Reactivity of Single-Atom Alloys as Easy as Counting to Ten

Single-Atom Alloys (SAAs) have recently emerged as highly active and selective alloy catalysts. Unlike pure metals, SAAs escape the well-established conceptual framework developed nearly three decades ago for predicting catalytic performance. Here, based on high throughput density functional theory calculations, we reveal a 10-electron count rule for the binding of adsorbates on the dopant of SAA surfaces. A simple molecular orbital approach rationalises this rule and the nature of the adsorbate/dopant interaction. In addition, our intuitive model can accelerate the rational design of SAA catalysts. Indeed, we illustrate how the unique insights provided by the electron count rule help identify the most promising dopant for an industrially relevant hydrogenation reaction, thereby reducing the number of potential materials by more than one order of magnitude.