Keith J. Stevenson

stevenson@cm.utexas.edu

Professor, Faculty

Research Group

Stevenson Group

Education

PhD, University of Utah, 1997
BA, University of Puget Sound, 1989

Postdoctoral Fellow, Northwestern University 1997-2000

Awards

SEAC Young Investigator, 2006
CSGS New Scholar Award, 2004
NSF CAREER Award, 2002

Affiliations

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

Analytical Chemistry, Electrochemistry and Surface Chemistry

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.

 

Representative Publications

Dylla, A.; Stevenson, K. J. “Facile Formation of Pt and PtPd Nanoparticles on Reactive Carbon-TiO₂ Nanosheets,” Chem. Comm. accepted.

 

Goran, J. M..; Lyon, J. L.; Stevenson, K. J. “Amperometric Detection of L-lactate Using Nitrogen Doped Carbon Nanotubes Modified with Lactate Oxidase,” Anal. Chem. 2011, 83(21), 8123-8129.

 

Wiggins-Camacho, J. D.; Stevenson, K. J. “A Mechanistic Discussion of Oxygen Reduction Reaction at Nitrogen doped Carbon Nanotubes,” J. Phys. Chem. C 2011, 115(40), 20002-20010.

 

Walker, E. K; Vanden Bout, D. A.; Stevenson, K. J. “Aqueous Electrogenerated Chemiluminescence of Self-Assembled Double-Walled Tubular J-Aggregates of Amphiphilic Cyanine Dyes,” J. Phys. Chem. C 2011, 115(5), 2470-2475.

 

Homan, K. A.; Chen, J.; Schiano, A.; Mohamed, M.; Willets, K. A.; Murugesan, S.; Stevenson, K. J.; Emelianov, S. “Silver Stars: Synthesis and Prospects as a Multifunctional Surface Enhanced Raman Scattering and Catalytic Substrate,” Adv. Mater. 2011, 21(9), 1673-1680.