CAREER: Methods for Targeted, High-Throughput Single-Entity Analyses

With this CAREER award, the Chemical Measurement and Imaging program in the Division of Chemistry is supporting Dr. Caleb Hill and his group at the University of Wyoming to design new experimental techniques to probe the reactivity of single, discrete entities. Understanding reactivity at the atomic or molecular scale has long been a central focus of the chemical sciences.

Scientists have traditionally approached these questions through the analysis of bulk properties, employing techniques which probe upwards of millions of individual atoms or molecules simultaneously. Unfortunately, many systems of interest, such as nanoparticles, are extremely heterogeneous and exhibit significant variations in reactivity that are “averaged out” in conventional studies.

The ability to obtain measurements that reflect the reactivity of single chemical entities could fundamentally improve our understanding of these systems. These techniques utilize small pipets as multipurpose tools to manipulate the position of single entities within a sample and to characterize their chemical behavior. The techniques are being validated and then applied to identify promising electrocatalyst materials for applications such as water splitting and CO2 reduction.

Complementing these research efforts, the Hill group is also establishing a "Measure Anything" outreach program focused on measurement science, enabling K-12 students across Wyoming to design their own research projects that utilize analytical facilities at the University of Wyoming.

Heterogenous chemical systems play an important role in many modern technologies, but their design presents unique challenges not found in the traditional chemical world of small molecules. Entity-to-entity variations within heterogeneous ensembles make the elucidation of meaningful structure-function relationships difficult when using conventional analytical techniques.

The ability to obtain measurements that reflect the reactivity of single chemical entities, such as nanoparticles, could fundamentally change the way heterogeneous chemical systems are developed. In the Hill lab, electroanalytical techniques are being developed to produce quantitatively-reliable single-entity data at the throughputs necessary to serve as a practical tool for guiding systems design.

Small pipets “dispense” individual entities at well-defined locations within a sample and probe the electrochemical behavior of these entities in a targeted fashion. The research entails both fundamental studies of each step of this single-entity electroanalytical approach and assessment of its practical utility to explore the reactivity of complex, high entropy alloy electrocatalyst materials.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.