Designing single-site alloy catalysts using a degree-of-isolation descriptor

Geometrically isolated metal atoms in alloy catalysts can target efficient and selective catalysis. However, the geometric and electronic disturbance between the active atom and its neighbouring atoms, that is, diverse microenvironments, makes the active site ambiguous. Herein, we demonstrate a methodology to describe the microenvironment and determine the effectiveness of active sites in single-site alloys. A simple descriptor, degree-of-isolation, is proposed, considering both electronic regulation and geometric modulation within a PtM ensemble (M = transition metal). The catalytic performance of PtM single-site alloy is examined thoroughly using this descriptor for an industrially important reaction, propane dehydrogenation. The volcano-shaped isolation-selectivity plot reveals a Sabatier-type principle for designing selective single-site alloys. Specifically, for a single-site alloy with a high degree-of-isolation, alternation of the active centre has a great impact on tuning selectivity, validated by the outstanding consistency between experimental propylene selectivity and the computational descriptor. A simple descriptor called degree-of-isolation is proposed to describe the microenvironment and determine the effectiveness of active sites in single-site alloys. For a single-site alloy with a high degree-of-isolation, alternation of the active centre strongly affects the selectivity.

Automated summary

In this study, a methodology was proposed to describe the microenvironment and determine the effectiveness of active sites in single-site alloys, using a simple descriptor called degree-of-isolation, which considers both electronic regulation and geometric modulation within a PtM ensemble. The catalytic performance of PtM single-site alloy for propane dehydrogenation was thoroughly examined, revealing a volcano-shaped isolation-selectivity plot that shows a Sabatier-type principle for designing selective single-site alloys.