3rd International Nanotechnology Conference & Expo
May 7-9, 2018, Rome, Italy
Plasmonic Catalysis: Heating vs. Hot Electrons
1Department of Chemistry, Duke University, USA
2Army Aviation & Missile RD&E Center, USA
3Optics Group, Department of Applied Physics, University of Cantabria, Spain
4Department of Physics, Duke University, USA
In plasmon-enhanced heterogeneous catalysis, illumination accelerates reaction rates by generating hot carriers and hot surfaces in the constituent nanostructured metals. In order to understand how photo-generated carriers enhance the non-thermal reaction rate, the effects of local heating and thermal gradients in the catalyst bed must be confidently and quantitatively characterized. This is a challenging task considering the conflating effects of light absorption, heat transport, and reaction energetics. Here, we introduce a methodology to distinguish the thermal and non-thermal contributions from plasmon-enhanced catalysts, demonstrated by illuminated rhodium nanoparticles on oxide supports to catalyze the CO2 methanation reaction. By simultaneously measuring the total reaction rate and the temperature gradient of the catalyst bed, the effective thermal reaction rate may be extracted. The residual non-thermal rate of the plasmon-enhanced reaction is found to grow with a super-linear dependence on illumination intensity, and its apparent quantum efficiency reaches ~46% on a Rh/TiO2 catalyst at a surface temperature of 350 °C. Heat and light are shown to work synergistically in these reactions: the higher the temperature, the higher the non-thermal efficiency in plasmon-enhanced catalysis.
Jie Liu is currently the George B Geller Professor of Chemistry at Duke University. He earned a B.S. in Chemistry from Shandong University in 1987 and a Ph.D. in Chemistry from Harvard University in 1996. His research interests include synthesis and chemical functionalization of nanomaterials, plasmonic catalysis, nanoelectronic devices, scanning probe microscopy, and carbon nanomaterials. As a faculty member, Professor Liu has received the DuPont Young Professor Award, Outstanding Oversea Young Investigator Award from NSF-China, Ralph E. Powe Junior Faculty Enhancement Award from Oak Ridge Associated Universities, and Bass Professorship from Duke University for excellence in teaching and research. He is elected as a Fellow in AAAS (2013), APS (2014) and RSC (2013). He also serves as an associate editor for RSC journal Nanoscale since 2012.