- Yuanyuan Li, The State University of New York at Stony Brook
In past decades, great efforts have been made in improving synthesis methods, developing characterization methods, and enhancing the catalytic properties and performances of catalytic nanoparticles. These efforts were motivated by the complexity of nanocatalysts which challenges the sample preparation and characterization methods, but on the other side is the key to control particle structure for better catalytic properties. In this talk, I am going to review our work on supported nanocatalysts with heterogeneity existing between clusters, within clusters, and between clusters and supports, and specifically answer two questions: 1) How to study systems with heterogeneity? For these systems, it is challenging but essential to track changes of different species involved in the system to determine the structure-property correlation, and to understand the working mechanism. A portable micro reactor, versatile to both spectroscopy and microscopy techniques, was therefore developed and applied for operando investigations of structural dynamics and speciations of supported nanocatalysts. And 2) Can we take advantage of structural heterogeneity for making novel materials? Yes. By controlling the support-particle interactions, we have partial Ni atoms formed silicate with the support, and the rest goes into the PtNi bimetallic cluster. Such complex heterogeneity facilitates the stabilization of the bimetallic structure in which Ni atoms singly dispersed onto Pt cluster forming a nanosized NiPt3 intermetallic structure with good activity, good stability and greatly enhanced selectivity for the reaction of reverse water gas shift.