MSE Colloquium Series
Fall Quarter 2013
Fridays at 3:15 to 4:45 in McCullough Building Room 115
Prof. Matthew Kanan
Turning CO2 into Liquid Fuel
Abstract: Electrochemical reduction of CO2 provides a link between renewable electricity and carbon-based fuel. Catalysts suitable for an electrolytic device must reduce CO2 and its derivatives with high selectivity and energetic efficiency using H2O as the H+ source and produce a fuel of choice. Metal electrodes in their bulk form are inefficient and unselective CO2 reduction catalysts. This talk will describe our development of “oxide-derived” metal nanoparticles, which are prepared by reducing metal oxide precursors. This process kinetically traps metastable nanoparticle structures with unique catalytic properties. I will describe examples of these catalysts that electrochemically reduce CO2 to CO at potentials close to the thermodynamic minimum as well as a catalysts that selectively reduce CO to multi-carbon oxygenates. The catalysts operate in water at ambient temperature and pressure and are remarkably robust. The structural origins of the catalytic activity will be discussed based on diffraction and high-resolution electron microscopy. Oxide-derived metal nanoparticles enable a two-step electrochemical conversion of CO2 to ethanol that could make CO2 a valuable feedstock for synthetic liquid fuel.
Bio: Matt Kanan is an Assistant Professor in the Department of Chemistry at Stanford. His research focuses on challenges in catalysis for renewable energy applications and fine chemical synthesis. His group has pioneered a new class of heterogeneous catalysts for electrochemical carbon fuel synthesis and experimental studies of electrostatic effects on the selectivity of catalytic reactions. Prior to Stanford, Matt was an NIH Postdoctoral Researcher in inorganic chemistry at MIT and did his Ph.D. research in organic chemistry at Harvard.
Prof. Allen J. Bard
Scanning Electrochemical Microscopy (SECM) for Photocatalyst Discovery and Improvement – Myths and Realities of Solar Fuels
Abstract: Renewed interest in the utilization of solar energy to produce fuels has led to intense activity in the area of photoelectrochemical (PEC) systems. A key issue in the design of practical systems is the discovery of a photocatalyst, generally a semiconductor material that has the required efficiency, stability, and cost characteristics. These are functions of the chemical composition and morphology of the semiconductor material. Despite almost 40 years of research in this area, a suitable photocatalyst has not yet been found.
Scanning electrochemical microscopy (SECM), which involves studying electrochemical reactions at a closely spaced ultramicroelectrode (UME) tip and a substrate, can be used to screen photocatalysts. In this application the SECM tip is replaced by a modified optical fiber. A robotic piezoelectric dispenser is used, followed by appropriate treatments, to prepare arrays composed of ~300 µm size photocatalyst spots with different compositions onto a fluorine-doped tin oxide (FTO) substrate. The scanning tip is a fiber optic, with or without a conducting detecting ring electrode, connected to a xenon lamp, which is rapidly scanned over the array. In this arrangement the photocatalytic performance of each spot can be evaluated by measuring the substrate photocurrent. The technique allows scans at different substrate potentials, so that the photocurrent-potential behavior can be recorded. Moreover products of the photoreaction can be measured at the tip ring electrode surrounding the fiber optic.
The technique has been used to evaluate effects of modifications (doping) of semiconductor materials, like bismuth vanadate by various metals, followed by testing of the best compositions in larger photoelectrochemical cells. Cells that can produce hydrogen and oxygen (water splitting) with modest efficiency can be fabricated with these materials with no externally applied voltage or sacrificial reagents.
Bio: Allen J. Bard was born in New York City on December 18, 1933 and grew up and attended public schools there, including the Bronx High School of Science (1948-51). He attended The City College of the College of New York (CCNY) (B.S., 1955) and Harvard University (M.A., 1956, PhD., 1958).
Dr. Bard joined the faculty at The University of Texas at Austin (UT) in 1958, and has spent his entire career there. He has been the Hackerman-Welch Regents Chair in Chemistry at UT since 1985. He spent a sabbatical in the CNRS lab of Jean-Michel Savéant in Paris in 1973 and a semester in 1977 at the California Institute of Technology, where he was a Sherman Mills Fairchild Scholar. He was also a Baker lecturer at Cornell University in the spring of 1987 and the Robert Burns Woodward visiting professor at Harvard University in 1988.
Hendrik Bluhm, Ph.D.
Interfacial Chemistry of Surfaces Under Ambient Relative Humidity
Abstract: The interaction of water vapor with surfaces plays a major role in many processes in the environment, atmosphere and technology. Weathering of rocks, adhesion between surfaces, and ionic conductance along surfaces are among many phenomena that are governed by the adsorption of molecularly thin water layers under ambient humidities. Ambient pressure photoelectron spectroscopy (APXPS) is an excellent method for the investigation of the properties of the interfacial chemistry of surfaces under reaction conditions. In this talk we will discuss the application of APXPS to the study of the interaction of water vapor with surfaces that are relevant in catalysis, electrochemistry, and environmental science, in particular metals and metal oxides.
Bio: Hendrik Bluhm is a Senior Scientist in the Chemical Sciences Division at Lawrence Berkeley National Laboratory. He obtained his M.Sc. in Crystallography from the University of Leipzig (Germany) and his Ph.D. in Physics from the University of Hamburg (Germany). After a postdoc in the group of Miquel Salmeron at LBNL he joined the Fritz Haber Institute of the Max Planck Society in Berlin, before moving back to LBNL and his current position. His research focuses on the interfacial chemistry of surfaces (e.g., metal oxides, ice, and aqueous solutions) under relevant environmental conditions, as well as the development of new experimental methods for the investigation of interfaces under operating conditions. Bluhm is a AAAS Fellow and a recent recipient of a Bessel Award from the Alexander von Humboldt Foundation.
Prof. Bianxiao Cui
At the Nano-Bio interface: probing live cells with vertical nanosensors
Abstract: The rapidly evolving field of nanotechnology creates new frontiers for biological sciences. Recently, we and other groups show that vertical nanopillars protruding from a flat surface support cell survival and can be used as subcellular sensors to probe biological processes in live cells. In particular, we are exploring nanopillars as electric sensor, optical sensors, and structural probes. As an electrode sensor, nanopillars electrodes offer several advantages such as high sensitivity, subcellular spatial resolution, and precise control of the sensor geometry. We found that the 3D topology of the nanopillars electrodes is crucial for its enhanced signal detection. The high membrane curvature induced by vertical nanopillars significantly affects the distribution of curvature-sensitive proteins and stimulates several cellular processes in live cells. Our studies show a strong interplay between biological cells and nano-sized sensors, which is an essential consideration for future development of interfacing devices.
Bio: Dr. Bianxiao Cui is an Assistant Professor of Chemistry at Stanford University. She holds a Ph.D. degree in Physical Chemistry from the University of Chicago under the supervision of Prof. Stuart Rice, working on dynamic heterogeneity and phase transition in colloidal liquid. After completing Ph.D., she worked as a postdoctoral scholar with Prof. Steven Chu on single molecule imaging of nerve growth factor signal transduction in neurons. She joined the faculty of Stanford University in 2008. Her main area of interest is to develop quantitative tools to study signal transduction in neurons. Her recent awards and distinctions include NIH New Innovator Award, NSF CAREER award, Packard Fellowships in Science and Engineering, Hellman Scholar, Searle Scholar Award and Dreyfus New Faculty award.
Prof. Yue Wu
Advanced Nanostructured Thermoelectric Materials for Waste Heat Recovery
Prof. Eric Pop
Energy in Electronics: From Graphene to Phase-Change Materials
Abstract: Energy use and conversion are important for the design of low-power electronics and energy-conversion systems. This is also a rich domain for both fundamental discoveries as well as technological advances. This talk will present recent highlights from our studies of energy in novel nanoelectronics. We have investigated both Joule heating and Peltier cooling in graphene transistors, thermal transport in graphene nanoribbons, and engineering of high-field current transport in graphene interconnects. We have also examined fundamental limits of data storage based on phase change (rather than charge or spin), achieving energy dissipation two orders of magnitude below industry state-of-the-art, approaching femtojoules per bit. The results suggest new directions to improve nanoscale energy efficiency towards fundamental limits, through the design of geometry and materials.
Bio: Eric Pop is an Associate Professor of Electrical Engineering (EE) at Stanford. He was previously with the University of Illinois Urbana-Champaign (UIUC), first as an Assistant then as an Associate Professor of Electrical & Computer Engineering (2007-13). His research interests lie at the intersection of nanoelectronics and nanoscale energy conversion systems. He received his Ph.D. in EE from Stanford (2005), the M.Eng./B.S. in EE and B.S. in Physics from MIT. He was a postdoc at Stanford and worked at Intel before joining UIUC. His honors include the Presidential Early Career (PECASE) Award, and Young Investigator Awards from the ONR, NSF, AFOSR and DARPA (2008-2010). He is an IEEE Senior member, a member of APS and MRS, and the Technical Program Chair of the IEEE Device Research Conference (DRC). More information about the Pop Lab can be found online at http://poplab.stanford.edu.
Prof. LaShanda Korley
Design rules from Nature for new material development
Abstract: Taking clues from nature, we are interested in understanding the design rules employed by nature and applying these strategies to the development of mechanically-enhanced and tunable materials. Of particular interest is the use of self-assembling small molecules in natural composites to tune mechanical response and provide potential stimuli-responsive behavior. In one approach, we have fabricated polymer nanocomposites inspired by natural materials using self-assembling small molecules as the filler material in an elastomeric matrix. Self-assembled nanofibers (~25 nm diameter, ~several microns in length) were obtained in a range of solvents. Composites were fabricated using a facile processing strategy to reveal uniform films with strong-matrix filler interactions. An almost two order of magnitude increase in the tensile storage modulus of these bio-inspired polymer composites in the rubbery regime was demonstrated for this material, highlighting the interplay between hierarchical structures, self-assembly, and mechanical response in new materials design. Another pathway toward bio-inspired nanocomposites is the utilization of electrospun nanofibers as the dispersed, high modulus filler low glass transition materials. We have demonstrated water-responsive mechanics in these systems via strategic control of filler-matrix interfacial interactions and hierarchical design of the nanofiber filler. Beyond composites, we have also generated layered constructs via a melt co-extrusion process that synergistically combine soft and hard materials for mechanical enhancement. These material platforms have applications in barrier technology, therapeutic delivery, and packaging.
Bio: LaShanda T.J. Korley joined the faculty of Case Western Reserve University (CWRU) in July 2007 as an Assistant Professor in the Department of Macromolecular Science and Engineering and was appointed to the Nord Distinguished Assistant Professorship in July 2009 and the Climo Assistant Professorship in 2012. LaShanda Korley earned a B.S. in Chemistry and Engineering from Clark Atlanta University and a B.S. in Chemical Engineering from Georgia Institute of Technology in 1999 as an ACS Scholar. Dr. Korley completed her doctoral studies at Massachusetts Institute of Technology in the Department Chemical Engineering and the Program in Polymer Science and Technology in 2005. LaShanda Korley was the recipient of the Provost’s Academic Diversity Postdoctoral Fellowship at Cornell University, where she completed a two-year postdoctoral appointment.
Her research focuses on the development of mechanically-enhanced, multifunctional polymeric materials for a myriad of applications, including energy and sustainability, biomedical engineering, protective fabrics, and structural materials. She is the Leader of the Science and Technology Innovations Platform within the NSF Center for Layered Polymeric Systems (CLiPS). Dr. Korley’s research efforts have been recognized by a National Science Foundation (NSF) CAREER Award, NSF BRIGE Award, a 3M Nontenured Faculty Grant, and a DuPont Young Professor Award. In 2012, Prof. Korley participated in the Japanese/American Frontiers of Science Symposium as a Kavli Fellow and the National Academy of Engineering’s U.S. Frontiers of Engineering Symposium. She was recently nominated (1 of 6 internationally) for the Young Talent Award, Polymers for Advanced Technologies Congress 2013.
Prof. Thomas Jaramillo
Developing electrocatalyst materials for chemical transformations in renewable energy
Abstract: Chemical transformations are ubiquitous in today's global-scale energy economy. The ability to catalyze chemical reactions efficiently will continue to be critically important as we aim to enable a future energy economy based on renewable, sustainable resources. This talk will focus on our efforts to develop catalytic materials for ambient-temperature, ambient-pressure processes involving the electron-driven production and consumption of fuels and chemicals, reactions that could play key roles for future energy technologies. More specifically, this talk will address catalyst development for electrocatalytic H2 generation from water and the synthesis of hydrocarbons and alcohols from CO2. If coupled to renewable sources of electricity (e.g. wind and solar), these two reactions could produce important fuels and industrial chemicals in a sustainable manner, avoiding fossil resources. This talk will also discuss recent efforts to develop improved catalysts for the oxygen reduction reaction (ORR), a major challenge in developing more efficient fuel cells and metal-air batteries. Common catalyst materials for these three reactions face challenges in terms of activity, selectivity, stability, and/or cost and earth-abundance. This talk will describe approaches used in our research group to understand the governing principles guiding the reaction chemistry, as well as strategies to tailor the surface chemistry of materials through control of morphology, stoichiometry, and surface structure at the nano- and atomic-scale in order to overcome performance barriers in catalyzing these reactions.
Bio: Thomas Francisco Jaramillo is an Assistant Professor in the Department of Chemical Engineering at Stanford University. Jaramillo is from San Juan, Puerto Rico, and came to Stanford University to pursue his B.S. in Chemical Engineering. Jaramillo then continued his education at the University of California at Santa Barbara, earning his M.S. and Ph.D. in Chemical Engineering. Jaramillo then conducted post-doctoral research at the Technical University of Denmark in the Department of Physics, as a Hans Christian Ørsted Post-doctoral Fellow. Jaramillo returned to Stanford in Fall 2007 to start his independent research career, where he has won a number of awards for his research efforts, including the Presidential Early Career Award for Scientists & Engineers (PECASE, 2011), the U.S. Dept. of Energy Hydrogen and Fuel Cell Program Research & Development Award (2011), the National Science Foundation (NSF) CAREER Award (2011), the Mohr-Davidow Ventures (MDV) Innovator Award (2009), the Hellman Faculty Scholar Award (2009), and the NSF BRIGE Award (2008).
Robert Kostecki, Ph.D.
Characterization of Electrochemical Interfaces and Interphases with Advanced Far and Near-Field Optical Probes
Abstract: Li-ion batteries are inherently complex and dynamic systems. Although often viewed as simple devices, their successful operation relies heavily on a series of complex mechanisms, involving creation or transformation of materials under non-equilibrium environments and formation of metastable phases and interphases. This paradigm of Li-ion system operation usually drives the battery toward irreversible physical and chemical conditions, which on one hand, assure devices operation over the lifespan of the application, and on the other hand, lead to battery ultimate degradation and failure.
Bio: Robert Kostecki is a Staff Scientist and Deputy Division Deputy for Science in the Environmental Energy Technologies Division at Lawrence Berkeley National Laboratory. He contributes to LBNL scientific, programmatic and strategic leadership in Energy and Environment areas through expanding existing research programs, assistance with development and maintenance of sponsor and partner relationships, and creating new research initiatives.