Catalytic reactions at alloy surfaces

Alloys have been widely studied for heterogeneous catalysis. Many bi- and multi-metallic alloys have enhanced performance as compared to their monometallic counterparts. However, a full understanding of the alloying effects was not well-established. In my Ph.D. works, density functional theory (DFT) was employed to disentangle the atomic ensemble, ligand, and strain effects of surfaces alloyed by transition metals. It is found that alloying elements with strong and weak adsorption properties could produce a surface ensemble with optimally tuned adsorbate binding, which can help to understand the mechanisms of catalytic reactions and design high-performance alloy catalysts. We developed a Tunability theory that quantifies the tuning of adsorbate bindings at the specific atomic ensembles on surface, which provides predictive power of theory for experiments. Using combined theoretical and experimental methods, we designed and studied new alloy catalysts for many industrially significant reactions including electrocatalysis, vapor-phase catalysis, and liquid-phase catalysis. We developed comprehensive theories that predominantly based on the atomic ensemble effect to unify theories and experiments for alloy heterogeneous catalysts. Most importantly, we show how fundamental understandings from theories can be precisely applied to efficient energy and environmental reactions. In addition, to accelerate atomistic simulations and materials design, we have been developing a machine learning framework that can fit the potential energy surfaces from the quantum mechanical data, which can help to partly replace expensive DFT calculations and reduce scientific costsChemistr