School of Humanities and Sciences

Showing 11-20 of 180 Results

  • Renata Kallosh

    Renata Kallosh

    Professor of Physics and, by courtesy, of Mathematics

    BioWhat is the mathematical structure of supergravity/string theory and its relation to cosmology?

    Professor Kallosh works on the general structure of supergravity and string theory and their applications to cosmology. Her main interests are related to the models early universe inflation and dark energy in string theory. She develops string theory models explaining the origin of the universe and its current acceleration. With her collaborators, she has recently constructed de Sitter supergravity, which is most suitable for studies of inflation and dark energy and spontaneously broken supersymmetry.

    She is analyzing possible consequences of the expected new data from the Large Hadron Collider (LHC) and the results of current and future cosmological observations, including Planck satellite CMB data. These results may affect the relationship between superstring theory and supergravity, and the real world. Professor Kallosh works, in particular, on future tests of string theory by CMB data and effective supergravity models with flexible amplitude of gravitational waves produced during inflation.

  • Matthew Kanan

    Matthew Kanan

    Associate Professor of Chemistry and Senior Fellow at the Precourt Institute for Energy

    BioAssociate Professor of Chemistry Matthew Kanan develops new catalysts and chemical reactions for applications in renewable energy conversion and CO2 utilization. His group at Stanford University has recently developed a novel method to create plastic from carbon dioxide and inedible plant material rather than petroleum products, and pioneered the study of “defect-rich” heterogeneous electro-catalysts for converting carbon dioxide and carbon monoxide to liquid fuel.

    Matthew Kanan completed undergraduate study in chemistry at Rice University (B.A. 2000 Summa Cum Laude, Phi Beta Kappa). During doctoral research in organic chemistry at Harvard University (Ph.D. 2005), he developed a novel method for using DNA to discover new chemical reactions. He then moved into inorganic chemistry for his postdoctoral studies as a National Institutes of Health Postdoctoral Research Fellow at the Massachusetts Institute of Technology, where he discovered a water oxidation catalyst that operates in neutral water. He joined the Stanford Chemistry Department faculty in 2009 to continue research into energy-related catalysis and reactions. His research and teaching have already been recognized in selection as one of Chemistry & Engineering News’ first annual Talented 12, the Camille Dreyfus Teacher-Scholar Award, Eli Lilly New Faculty Award, and recognition as a Camille and Henry Dreyfus Environmental Mentor, among other honors.

    The Kanan Lab addresses fundamental challenges in catalysis and synthesis with an emphasis on enabling new technologies for scalable CO2 utilization. The interdisciplinary effort spans organic synthesis, materials chemistry and electrochemistry.

    One of the greatest challenges of the 21st century is to transition to an energy economy with ultra-low greenhouse gas emissions without compromising quality of life for a growing population. The Kanan Lab aims to help enable this transition by developing catalysts and chemical reactions that recycle CO2 into fuels and commodity chemicals using renewable energy sources. To be implemented on a substantial scale, these methods must ultimately be competitive with fossil fuels and petrochemicals. With this requirement in mind, the group focuses on the fundamental chemical challenge of making carbon–carbon (C–C) bonds because multi-carbon compounds have higher energy density, greater value, and more diverse applications that one-carbon compounds. Both electrochemical and chemical methods are being pursued. For electrochemical conversion, the group studies how defects known as grain boundaries can be exploited to improve CO2/CO electro-reduction catalysis. Recent work has unveiled quantitative correlations between grain boundaries and catalytic activity, establishing a new design principle for electrocatalysis, and developed grain boundary-rich copper catalysts with unparalleled activity for converting carbon monoxide to liquid fuel. For chemical CO2 conversion, the group is developing C–H carboxylation and CO2 hydrogenation reactions that are promoted by simple carbonate salts. These reactions provide a way to make C–C bonds between un-activated substrates and CO2 without resorting to energy-intensive and hazardous reagents. Among numerous applications, carbonate-promoted carboxylation enables the synthesis of a monomer used to make polyester plastic from CO2 and a feedstock derived from agricultural waste.

    In addition to CO2 chemistry, the Kanan group is pursuing new strategies to control selectivity in molecular catalysis for fine chemical synthesis. Of particular interest in the use of electrostatic interactions to discriminate between competing reaction pathways based on their charge distributions. This effort uses ion pairing or interfaces to control the local electrostatic environment in which a reaction takes place. The group has recently shown that local electric fields can control regioselectivity in isomerization reactions catalyzed by gold complexes.