Displaying items by tag: keith stevenson
Keith J. Stevenson
Education & Training:
Department of Chemistry
University of Texas at Austin
PhD, University of Utah, 1997
BA, University of Puget Sound, 1989
Postdoctoral Fellow, Northwestern University 1997-2000
Analytical Chemistry, Electrochemistry and Surface Chemistry
Our research is aimed at understanding and controlling the kinetics and energetics of reactions occurring at scientifically interesting, technologically relevant solid/liquid interfaces. Driving our fundamental interest is the need to comprehend the intricate relationships between mass transport, surface reactivity, and interfacial structure. This information is useful for the design and optimization of superior chemical process technologies associated with the areas of chemical sensing, energy storage/conversion, photonics, microelectronics, and device miniaturization.
Nanostructured Materials for Energy Conversion and Storage
Thrusts in this area focus on the creation and study of new materials with improved chemical, electronic and structural properties for potential applications in catalysis and power source technologies (e.g., fuel cells and batteries). One goal is to prepare high surface area (>100 m2/g) and high porosity (>70 to 99%) materials with tailored composition and nanostructure (e.g., size, shape and orientation). For instance, we have prepared nanocarbons via chemical vapor deposition that are inherently catalytic for oxygen reduction and hydrogen peroxide decomposition. Current studies involve the synergistic tuning of these nanocarbon supports with more active metal catalysts to enhance catalytic performance.
Chemically-Responsive Composites for Analysis and Sensing
Projects in this area are directed toward the assembly of nanostructured materials (mesoporous, colloidal, sorptive or framework solids) and chemical composites (substrate-specific, activator/reporter molecule systems) for use in developing selective chemical sensing methodologies. By employing both conventional and non-conventional nano- and micro-patterning techniques in conjunction with chemical and electrochemical deposition methods, we have been able to fabricate composite assemblies that are useful as 1D and 2D optical transmission gratings in chemical sensing applications. In a separate project, we have utilized the redox activity of small molecules in a mediated, enzymatic electrochemical sensing scheme. This system enables ultra-low (<1 nM); quantitative detection of biogenic analytes (cholesterol, hydrogen peroxide).
Development of High Resolution Analytical Tools/Methods
Projects in this area focus on the development of improved analytical methods and tools for the spatial, temporal, and spectral investigation of materials and interfaces. Better comprehension of mechanistic factors obtained by these measurements allows for direct establishment of structure/composition/performance relationships. For instance, we have recently used spectroelectrochemical imaging schemes to study proton and lithium insertion at inhomogeneous metal oxides (e. g. MoO3, MoxW1-xO3, MnO2,). Information of this kind is useful for developing superior materials for batteries, flexible electronics, electrochromics, and solar cells. We also developed ultra-sharp, nanosized probe tips with controlled geometry and orientation. These probe provide enhanced spatial resolution for characterization of nanoscale, high-aspect ratio features commonly associated with microelectronic devices.
Center for Nano- and Molecular Science and Technology; IGERT: Atomic and Molecular Imaging; Texas Materials Institute; Welch Summer Scholar Program; Center for Electrochemistry; The Freshman Research Initiative
Honors and Awards:
Kavli Fellow, 2012
SEAC Young Investigator, 2006
CSGS New Scholar Award, 2004
NSF CAREER Award, 2002
Selected Peer-reviewed Publications:
1.Mefford, J. T.; Hardin, W. G.; Dai, S.; Johnston, K. P.; Stevenson, K. J. “Anion Charge Storage Through Oxygen Intercalation in LaMnO3 Perovskite Pseudocapacitor Electrodes,” Nat. Mater. 2014, 13(7), 726-732.
2. Hardin, W. G.; Mefford, J. T.; Wang, X.; Dai, S.; Ruoff, R. S.; Johnston, K. P.; Stevenson, K. J. “Tuning the Electrocatalytic Activity of Perovskites Through Active Site Variation and Support Interactions,” Chem. Mater. 2014 26, 3368−3376.
3. Goran, J.; Favela, C.; Stevenson, K. J. “Investigating the Electrocatalytic Oxidation of Dihydronicotinamide Adenine Dinucleotide at Nitrogen-Doped Carbon Nanotube Electrodes: Implications to Electrochemically Measuring Dehydrogenase Enzyme Kinetics,” ACS Catal. 2014 4, 2969-2976.
4. Redman, D. W.; Murugesan, S.; Stevenson, K. J. “Cathodic Electrodeposition of Amorphous Elemental Selenium From an Air- and Water-stable Room Temperature Ionic Liquid,” Langmuir 2014 30(1), 418-425.
5. Dasari, R.; Tai, K.; Robinson, D. A.; Stevenson, K. J. “Electrochemical Monitoring of Single Nanoparticle Collisions at Mercury Modified Platinum Ultramicroelectrodes,”ACS Nano 2014 8(5), 4539-4546.
6. Murugesan, S.; Quintero, O. A.; Chou, B. P.; Xiao, P.; Park, K.-Y.; Hall, J. A.; Jones, R. A.; Henkelman, G.; Goodenough, J. B.; Stevenson, K. J. “Wide Electrochemical Window Ionic Salt for use in Electropositive Metal Electrodeposition and Lithium Ion Batteries,” J. Mater. Chem. A 2014, 2, 2194–2201.
7. Dylla, A.; Henkelman, G.; Stevenson, K. J. “Lithium Insertion in Nanostructured TiO2 Architectures,” Acc. Chem. Res. 2013, 46(5) 1104-1112.
8. Membreno, N.; Xiao, P.; Park, K.-Y.; Goodenough, J. B.; Henkelman, G.; Stevenson, K. J. “In Situ Raman Study of Phase Stability of Li3V2(PO4)3 upon Thermal and Laser Heating,” J. Phys. Chem. C 2013, 117(23), 11994-12002.
9. Johnson, J. A.; Makis, J.; Marvin, K. A.; Rodenbusch, S. E.; Stevenson, K. J. “Size-dependent Hydrogenation of p-Nitrophenol with Pd Nanoparticles Synthesized by Polyamido(amine) Dendrimer Templates,” J. Phys. Chem. C 2013 117(44), 22644-22651.
10. Dasari, R.; Robinson, D.; Stevenson, K. J. “Ultrasensitive Electroanalytical Tool for Detecting, Sizing and Evaluating the Catalytic Activity of Platinum Nanoparticles,” J. Amer. Chem. Soc. 2013, 135(2), 570-573.
11. Goran, J. M.; Mantilla, S. M.; Stevenson, K. J. “Influence of Surface Adsorption on Interfacial Electron Transfer of Flavin Adenine Dinucleotide and Glucose Oxidase at Carbon Nanotube and Nitrogen-doped Carbon Nanotube Electrodes,” Anal. Chem. 2013, 85(3), 1571-1581.
12. Hardin, W. G.; Slanac, D. A.; Wang, X.; Dai, S.; Johnston, K. P.; Stevenson, K. J. “Highly Active, Non-precious Metal Perovskite Electrocatalysts for Bifunctional Metal Air Battery Electrodes,” J. Phys. Chem. Lett. 2013, 4, 1254-1259.
Published in People