Chemistry and Photochemistry on Plasmonic Nanoparticle Surfaces

Professor Hui Wang of the University of South Carolina is studying detailed mechanisms of catalytic and photocatalytic molecular transformations on nanostructured metal surfaces through combined experimental and computational efforts. Mechanistic insights gained from this project will lay a critical knowledge foundation, built upon which nanoscale light-matter and surface-adsorbate interactions can be judiciously fine-tuned and leveraged for chemoselective and regioselective functionalization of nanoparticle surfaces, paving the way for advanced manufacturing of functional nanomaterials for targeted applications in catalysis, photocatalysis, optoelectronics, molecular sensing, and nanobiomedicine. The proposed research will be further integrated with educational activities and workforce development by creating interdisciplinary research training opportunities for graduate, undergraduate, and high school students. Collaborating with high school chemistry teachers, Professor Wang will build a long-term educational partnership between Dreher High School and University of South Carolina through outreach activity development and Chemistry Olympiad coaching. Professor Hui Wang and his research team at the University of South Carolina seek to develop detailed mechanistic understanding of several unconventional catalytic and photocatalytic reactions triggered by metal nanoparticle surfaces. Surface-enhanced Raman spectroscopy (SERS) will be utilized as an in situ molecule-fingerprinting tool to fine-resolve detailed kinetic features of the interfacial molecule-transforming processes and unravel the underlying reaction pathways. The results of deliberately designed in situ SERS measurements will be further corroborated by density functional theory calculations to fully understand the origin of the experimental observations. The proposed research is hypotheses-driven, aiming to seek answers to the following fundamental questions: (1) How do nanoparticle-adsorbate interactions and the local chemical environments influence the pathway selection and reaction outcomes of catalytic molecular transformations? (2) How do resonantly excited localized plasmons in metallic nanoparticles regulate the activation energy barriers of the rate-limiting steps in multistep cascading catalytic reactions? (3) How to harness plasmonic photophysical and photochemical effects for chemoselective bond cleavage and bond formation in molecular adsorbates on metal nanoparticle surfaces? Success in the proposed project will push the understanding of nanoparticle surface chemistry and plasmonic photochemistry toward an unprecedented level of depth, quantitativeness, and comprehensiveness. 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.