Mechanistic Insights into Electrocatalytic Fuel Formation & Combustion
Yogesh Surendranath from MIT
Wednesday, August 6th 2014; Noon; Barus & Holley 190
Host: The Center for the Capture and Conversion of CO2
Abstract: The widespread utilization of renewable energy will require energy dense and cost-effective methods for its storage and recovery. This challenge could be met by pairing electrolytic reduction of carbon dioxide to liquid fuels with subsequent recombination of the fuel and O2 in a fuel cell. The net process would comprise a carbon-neutral fuel cycle mimicking natural photosynthesis and respiration. A key obstacle impeding practical CO2-to-fuels conversion is the low selectivity for CO2 reduction relative to H2 evolution on metal electrodes. Rational approaches to improved CO2 reduction selectivity have been impeded by the lack of mechanistic understanding of the factors that control this kinetic bifurcation, including the role of transport limitations at the electrode surface. By interrogating CO2 reduction on a rotating disk electrode, we have begun to uncover the activation-controlled kinetics of this reaction and the mechanistic basis for selective fuel formation. A key obstacle impeding widespread utilization of fuel cells is the high cost and low terrestrial abundance of platinum catalysts used to mediate the kinetically demanding oxygen reduction reaction (ORR). We have recently observed that sequential room temperature electrodeposition of atomic layers of Co and S gives rise to a highly activity ORR catalyst as a conformal Co9S8 nanofilm on inert electrodes. Leveraging this tunable synthetic method, we have uncovered key insights into the mechanism of oxygen reduction on this promising earth abundant catalyst.
Bio: The Surendranath Lab is focused on addressing global challenges in the areas of chemical catalysis, energy storage and utilization, and environmental stewardship. Fundamental and technological advances in each of these areas require new methods for controlling the selectivity and efficiency of inner-sphere reactions at solid-liquid interfaces. Our strategy emphasizes the bottom-up, molecular-level, engineering of functional inorganic interfaces with a current focus on electrochemical energy conversion.