CAS: Single-Molecule Specific Voltammetry: Quantifying Reaction Products of Electrocatalysis at Single Particle Level

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With support from the Chemical Measurement & Imaging program, and partial co-funding from programs in Macromolecular, Supramolecular, and Nanochemistry; Chemical Catalysis; and Chemical Structure, Dynamics, and Mechanisms – A, Professor Chang and his research team at the University of Massachusetts - Dartmouth are developing a new chemical analysis tool to enable detailed studies of electrochemical reaction mechanisms associated with conversion of carbon dioxide (CO2) to less harmful materials, a promising route to mitigating climate change. Specifically, the team is developing a novel technique, named single-molecule specific (SMS) voltammetry, to probe the performance of single nanoparticles as catalysts for CO2 reduction reactions. The research may advance our ability to design electrocatalysts that efficiently convert CO2 into fuels. A broad educational program introduces this research to undergraduate and graduate students, and includes outreach activities to inspire underrepresented K-12 students in South Massachusetts to pursue careers in STEM fields.This project aims to develop a platform to quantify the products of electrochemical CO2 reduction on single nanoparticles, and to reveal the morphology-dependent performance and stability of nanoelectrocatalysts. Carbon monoxide (CO) formation on Au nanoparticles is used as a model reaction. Specifically, the research is addressing the following objectives: (1) Demonstration of the ability of single-molecule specific (SMS) voltammetry to quantify CO formation on single nanoparticles. (2) Assessment of the effects of interparticle and intraparticle heterogeneity on CO formation on single electrocatalysts. (3) Identification of the mechanism(s) of nanoparticle instability during CO2 reduction reactions. By combining SMS voltammetry, super-resolution fluorescence, and electron microscopies, the research team is striving to elucidate the morphology-dependent activity for CO formation and super-resolve the facet-dependent active sites on single nanoelectrocatalysts. Improved understanding of the correlation between the activity and stability of electrocatalysts and the origin of nanoparticle instability in CO2 reduction are parallel aims. These research efforts are envisioned to provide the knowledge needed for rational design of nanoelectrocatalysts for CO2 reduction reactions.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.