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Understanding Transport and Chemical Phenomena in Solar Fuel Generators for Water and Carbon Dioxide Splitting

Speaker: Rohini Bala Chandran, Associate Professor, University of Michigan, Ann Arbor
Host: Energy and Efficiency Institute
Date: 11/18/2019
Time: 12:15pm to 1:30pm
Location: 1605 Tilia Street, West Village, UC Davis

Abstract: Green plants make complex hydrocarbons from available sunlight, water and carbon dioxide – can we take a leaf from nature’s book? Solar-fuel technologies offer the potential to harness and store the Earth’s most abundant, yet intermittently available, energy resource in the form of energy dense chemicals such as hydrogen and hydrocarbon compounds, derived from water and carbon dioxide. I will present two routes for solar-fuels production, with a focus on probing the complex coupling of mass, momentum, energy and charge transport, and kinetic processes, and its impacts on the materials-to-device scale performance. One approach utilized concentrated solar power to drive an isothermal, cerium dioxide based redox cycle for carbon dioxide and water splitting at temperatures as high as 1500 °C. I will describe how the development of a computational transport and kinetic reactor model was key to achieve design innovations in the reactor, optimize operating conditions, and facilitate physical interpretation of experimental data. In the second approach, a particle-suspension reactor was designed to effect photoelectrochemical solar-hydrogen production from water via a Z-scheme mechanism with two photosystems comprising of semiconductor light absorbers and soluble redox shuttles, similar to natural photosynthesis. In addition to the optical properties of the semiconductors, transport and surface-specific kinetic properties of the redox shuttle have implications on the solar-to-fuel energy conversion efficiency. I will conclude with a discussion on central challenges for solar-fuel technologies and current research directions in my on the topics of radiative transport in particle- laden flows, and solar-powered devices for wastewater treatment.

Bio: Rohini Bala Chandran is an Assistant Professor in Mechanical Engineering at the University of Michigan since January 2018. Previously, she was a postdoctoral research fellow at Lawrence Berkeley National Lab, and obtained an M.S. and Ph.D. from the University of Minnesota, Twin Cities, in Mechanical Engineering. At Michigan, Prof. Bala Chandran leads the Transport and Reaction Engineering for Sustainable Energy Lab (TREE Lab), where she and her students perform multidisciplinary research in the areas of thermal and fluid sciences, multiscale computation, electrochemical engineering, and semiconductor physics. Specifically, the group applies computational models integrated with experimental analyses to probe the interplay of heat and mass transfer, radiative transport and chemical reactions that play a central role in a host of thermal, thermochemical, and electrochemical energy systems. Prof. Bala Chandran and her students apply this knowledge for applications of concentrated solar power technologies, solar fuel generators and wastewater treatment devices.