The Linic Lab is on the leading edge of research into the fundamentals and applications of new and improved heterogeneous photocatalysts. We were among the first groups to report visible light enhanced performance of metal nanoparticle catalysts (Ag, Au, and Cu) due to localized surface plasmon resonance. Our work now focuses on understanding the surface mechanisms that cause enhancement and in developing new catalysts that combine optimal plasmonic and catalytic properties within a single catalyst. We are also working on photoelectrochemical systems for applications in water splitting and fuel cells.
In the ever-expanding field of photocatalysis, our group places an emphasis on gaining a thorough understanding of the mechanisms involved in heterogeneous photocatalytic systems at the molecular level. Our approach combines the results of kinetic studies with rigorous in-situ and ex-situ catalyst characterization as well as computational modeling of these systems.
Plasmonic photocatalyst design and implementation
Our lab was one of the first to report and explain the mechanisms behind the use of plasmonic metal nanoparticles (Ag, Au, and Cu) as a driver for photocatalytic enhancement on both semiconductors and directly on plasmonic metals. The unique dielectric properties of plasmonic metal nanoparticles allow them to focus incoming electromagnetic radiation (i.e. light) directly onto the surface of catalyst particles, where chemical transformations occur. By doing so, these catalysts are able to efficiently convert visible light into chemical energy that can be used to drive chemical reactions. Experimentally our group has used plasmonic metal nanoparticles to enhance reaction rates and selectivities for industrially important reactions. We are now working on new catalysts that combine multiple metals to broaden the applications of plasmonic catalysts. We have also coupled plasmonic metals with semiconducters in photoelectrochemical systems to improve the efficiency of processes such as hydrogen evolution. Current members working in this area include Paul Hernley, Umar Aslam, Young Geun Park, and Joseph Quinn.
Mechanistic understanding of photocatalytic systems
Currently, the complex mechanisms that cause photocatalytic enhancement on plasmonic metal nanoparticle systems are not fully understood. Our group combines experimental characterization studies with computational modeling to gain insight into these mechanisms at the molecular level. Techniques such as in situ UV-visible and Raman spectroscopy allow us to monitor the optical properties of catalysts and how they may change in response to exposure to light or the introduction of reactants. Our group's dedicated computing cluster allows us to perform complex DFT (density functional theory) and FDTD (finite difference time domain) model calculations of the catalyst systems we seek to understand. In combination, these experimental and computational results have continued to shed light on many of the important mechanistic aspects of plasmonic photocatalysts, which in turn leads to better catalyst and reaction system design and implementation. Current members working in this area include Matthew Morabito, Robert Campana, and Calvin Boerigter.