Super-Resolution Imaging of Surface Adsorption on Single Nanoparticles for Electrochemical Dechlorination

Cornell University, Ithaca NY

Investigators

Abstract

With support from the Macromolecular, Supramolecular and Nanochemistry (MSN) Program in the Division of Chemistry, Professor Peng Chen of Cornell University is applying and developing high-resolution imaging approaches to quantify the adsorption behaviors on single palladium (Pd) nanoparticles of molecules involved in electrochemical hydrodechlorination reactions as well as to determine their relations to the electrochemical potential and the original Pd nanoparticle surface structure and size. Chlorinated hydrocarbons are extensively used in industrial and agricultural applications, but they are also environmental hazards. Dechlorination is a key detoxification process, for which electrochemical hydrodechlorination is more efficient and environmentally friendly by using electric power to drive reactions for which Pd nanoparticles are promising electrocatalysts. The research in the Chen group can generate fundamental knowledge that can help improve electrochemical dechlorination of chlorophenols, a large class of pollutants in aquatic environments, thus positively impact societal well-being. The imaging approaches are also generally applicable and thus can broadly impact measurement science in nanoscale materials science. For surface reactions, including electrocatalysis on nanoparticles, molecule-surface interactions are crucial. For Pd nanoparticle-catalyzed electrochemical hydrodechlorination little is known, however, about the quantitative adsorption behaviors of the chlorophenols and the product phenol on Pd surfaces, which are key steps in the electrocatalytic cycle. It is generally challenging to quantify adsorption under electrochemical reaction conditions, especially on nanoparticles, whose individuals can differ markedly in size and shape. The proposed research can provide quantitative insights into the energetics of reactant/intermediate/product adsorption on Pd nanoparticles at various applied electrochemical potentials and how they are related to the initial surface facet structure and particle size. This knowledge can guide the efforts of using dynamic electrochemical potential modulation to manipulate molecular adsorption on Pd-based electrocatalysts to improve the efficiency of electrochemical hydrodechlorination. The graduate student working on this project is gaining experience at the forefront area of single-molecule catalysis as well as in the development of novel techniques for super-resolution imaging of nonfluorescent processes by optical microscopy. 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.