LEAPS-MPS: Utilizing Interband Transitions in Metallic Nanoparticles for Photocatalysis

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This award is funded in whole or in part under the American Rescue Plan Act of 2021 (Public Law 117-2). Professor Son Nguyen and the research group at the University of California at Merced intend to investigate how metallic, nanometer size particles absorb photons and accelerate chemical reactions. Through varying photon energy, observing the corresponding chemical products, and correlating the photoexcited state of the particles to the rate of product formation, the researchers intend to reveal the working mechanism of the particles. Successful implementation of the proposed work may provide some fundamental rules for preparing green materials for future chemical synthesis. The Nguyen group intends to assist under-represented students succeed in STEM fields by providing professional preparation and hands-on research experience in nanoscience and sustainable energy. These training activities are well suited to the missions of the University of California at Merced, including serving the Hispanic community and supporting first-generation college and economically disadvantaged students. In this project, the Nguyen group intends to reveal the catalytic mechanism induced by interband transitions to seek a new reaction mechanism and potential application of metallic nanoparticles via two main goals: i) establishing the catalytic mechanism and activities of hot holes for Suzuki coupling reactions and ii) expanding the catalysis of hot holes for other coupling reactions. Mesoporous nanoparticles will be utilized to solve the challenging spectral overlap of plasmon resonance and interband transitions. The plasmon resonance of the porous nanoparticles is shifted from the visible to near infrared region, allowing the Nguyen group to interrogate the photocatalysis induced by interband transitions in the visible region without spectral interference of the plasmon resonance. Control experiments with non-porous nanoparticle counterparts, in which interband transitions and plasmon resonance are spectrally overlapped, will allow the Nguyen group to differentiate the catalytic contribution from each photoexcitation regime. Several model reactions, including C-C and C-N couplings, will be studied to highlight the catalytic role and application of interband transitions. This project has the potential to stimulate research in nanomaterial-based photocatalysis and expedite the application of photochemistry for practical use.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.