Site-Resolved Rates in Heterogeneous Catalysis Exemplified By NO Decomposition

The ability to connect catalytic activity to materials properties has played a pivotal role in the rational design of heterogeneous catalysis. Herein, we present a novel method for predicting the activity of catalytic sites on-the-fly with atomic resolution and near DFT accuracy. Through the use of a series of linear scaling relationships, we show that the local stability (BE) of an active site can be used as a direct descriptor of catalytic activity. Our approach renders site-specific Sabatier-type volcano plots that offer a powerful tool to assess nanostructural as well as alloying effects in catalysis. This paves the way towards atomic-level design of heterogeneous catalysts for thermal and electrochemical applications.

Central to our approach is the use of a computationally highly efficient scheme for determining the variation of the BE over a nanostructure from the local chemical and coordination environment. By linear relationships, we first connect the BE and the adsorption energies (E_ad) of key adsorbates in catalytic processes, and second link the E_ad to activation barriers through BEP scaling relations. Through the use of a microkinetic model for the catalytic process of interest, the site-resolved effects of structure and alloying can be accurately captured on-the-fly on systems of >10 nm size.

Using NO decomposition over Pt-based catalysts as example, we showcase how our methods can be used to improve catalytic performance by comparing alloying, size and shape effects. E.g., for the (111) site of pure Pt, the BE is not located at the volcano peak (Fig 1.A). By alloying with, e.g., Au, the BE can be pushed towards weaker BE and increased activity (Fig 1.B and C). We find that Au-alloyed Pt-nanoparticles outperform pure Pt for all considered particle sizes and shapes, and we identify the optimal particle size for catalytic performance for this example.