Energy funneling in plasmonic nanocrystal composites for photocatalytic production of solar fuels

Bowling Green State University, Bowling Green OH

Investigators

Abstract

Energy funneling in plasmonic nanocrystal composites for photocatalytic production of solar fuels. Dr. Mikhail Zamkov of Bowling Green State University is developing a novel model system for solar energy conversion in colloidal nanostructures aimed toward improving their photocatalytic activity. The proposed nanomaterial architecture is designed to funnel the solar light into the center of a composite nanoparticle via a built-in antenna. The absorbed radiation is then routed toward the exterior of the nanoparticle to drive catalytic reactions on its surface. To enable an efficient catalytic cycle, a novel type of energy transfer mechanism between the antenna and the catalyst is employed. The proposed innovation makes use of judiciously engineered interfaces between inorganic domains of the composite nano-object to ensure a seamless transfer of the solar energy across the photocatalytic system. The catalytic nanostructures are rendered soluble, which allows combing the benefits of homogenous reactions on the surface (excellent activity and selectivity) with the facility of the heterogeneous systems to recycle the catalyst. These materials are particularly suited to drive aqueous phase reactions, including hydrogen production and environmental clean-up, with enhanced reactivity under the solar flux. The proposed project helps the investigator in his effort to continue to bring in several students from underrepresented groups each summer for a full-time research internship in the lab. The investigator also interfaces with several industrial partners to provide the undergraduate researchers with industrial laboratory experience. In this project, funded by the Chemical Catalysis Program, Dr. Mikhail Zamkov of Bowling Green State University focuses on the synergy of novel synthetic strategies and ultrafast spectroscopy techniques to explore a new class of photocatalytic materials utilizing composite colloidal nanostructures. The proposed nanomaterials combine several inorganic domains in a single nano-reactor designed to efficiently convert the solar radiation into a catalytically active state. The key innovation of the nanomaterial architecture lies in the plasmon-assisted light-harvesting scheme, which takes advantage of the strong electro-magnetic field that exists in metal nanoparticles to boost the production of excitons in the surrounding semiconductor shell. The excitation energy of the shell is then relayed to suitable oxidation/reduction catalysts on the surface. To ensure that different constituents of the composite nano-object work seamlessly, inter-domain interfaces are grown using molecular epitaxy. Such stoichiometric bonds, either covalent or ionic, reduce the density of defect states that dissipate the excitation energy enabling a high throughput of the absorbed radiation. The catalytic performance of the investigator's colloidal nanostructures are tested using common redox reactions in aqueous media, while the energy transfer processes are investigated using ultrafast spectroscopy techniques. As an active member of Building Ohio's Sustainable Energy Future and Science, Engineering & Technology Gateway Ohio programs, Professor Zamkov involves small teams of undergraduate students in this research project, introducing them to general concepts in ultrafast spectroscopy, material science, and chemical synthesis. Special efforts are made to involve minority students and students from underrepresented groups. Professor Zamkov also interfaces with several industrial partners to provide the undergraduate researchers with industrial laboratory experience.