(768e) Development of Predictive Structure-Reactivity Relationships for Multimetallic Catalyst Design

Alloys are an important class of materials that often exhibit unique physical and chemical characteristics, such as exceptional hardness or enhanced chemical reactivity. As such, alloys show promise for many applications including heterogeneous catalysis and electro-catalysis. While the potential for the utilization of alloys in heterogeneous catalysis and electro-catalysis is significant, predictive models relating the geometric structure of alloys to the catalytic reactivity are lacking.

In our studies, we have performed core level spectroscopies measurements and density functional theory calculations to investigate the impact of alloying on the electronic structure and chemical reactivity of metal sites. We have developed a model that allows us to accurately predict variations in adsorption energy on alloy surfaces based on easily accessible physical characteristics of the metal elements that form the alloy, mainly their electronegativity, atomic radius, and the spatial extent of valence orbitals. We will demonstrate the model by focusing on the electrochemical oxygen reduction reaction. The model permits rapid screening through an enormous phase space of alloy structures and compositions using analytical expressions instead of expensive quantum-chemical calculations. Since the model is grounded on validated theories of chemisorption on metal surfaces, it can be used for the identification and targeted manipulation of the critical electronic structure descriptors of catalytic activity and propose how these features can be obtained based on electronic structure engineering.

1. H. Xin, A. Holewinski, S. Linic, “Predictive Structure-Reactivity Models for Rapid Screening
of Pt-based Multimetallic Electrocatalysts for the Oxygen Reduction Reaction”, ACS Catalysis,
2, 12, (2012)
2. H. Xin, S. Linic, “Exceptions to the d-band Model of Chemisorption on Metal Surfaces: The
Dominant Role of Repulsion between Adsorbate States and Metal d-states”, J. Chem. Phys.
132, 221101, (2010)
3. H. Xin, N. Schweitzer, E. Nikolla, S. Linic, “Developing Relationships between the Local
Chemical Reactivity of Alloy Catalysts and Physical Characteristics of Constituent Metal Elements”,
J. Chem. Phys. 132, 111101, (2010)