Carol L. Korzeniewski - US grants

The electrocatalytic oxidation of small organic molecules forms the focus of the research of Professor Korzeniewski at Texas Tech University. This project, supported by the Analytical and Surface Chemistry Program, addresses the kinetics of formation of intermediates in the electrocatalytic oxidation of methanol using chromatography coupled with small volume electrolysis methods. The activation of water in these electrolytic processes is probed by monitoring the effect of the activation on the oscillatory voltammetry of CO on the platinum electrode. Information from these studies will enable the improved design of direct methanol fuel cells as well as the use of electrocatalysis for the destruction of organic contaminants in groundwater. A detailed understanding of the electrocatalytic oxidation of small organic molecules is important to the development of fuel cells and processes for remediation of contaminated groundwater sources. This research project studies the mechanisms of these processes using a combination of chromatographic detection of reaction intermediates and voltammetric probes of electrode kinetics.

The objectives of this Product Realization and Environmental Manufacturing Innovative Systems (PREMISE) Exploratory Research project are: (1) To conduct exploratory research into the feasibility of an alternative PCB recycling process based on cryogenic decomposition of the PCBs; (2) To establish an interdisciplinary research team that can develop a long-term collaboration that builds on the understanding developed in this project; (3) To evaluate the proposed recycling process against traditional PCB recycling processes in terms of recycle rate economics, energy consumption, and environmental performance; and (4) To examine the feasibility of reusing plastics in the proposed recycling process.

The proposed recycling process is cryogenic decomposition of the PCBs. The process takes advantage of the fact that at very low temperatures, polymeric materials become highly brittle. In addition, the residual stresses set-up in the PCB resins due to thermal expansion mismatch between the polymers and other materials on the PCB is expected to lead to a better separation than might otherwise be possible simply due to the embrittlement of the plastics. Actual laboratory experiments will be performed using a cryogenic test system.

Wide diffusion of electronic equipment and shortening of product lifecycles have caused a serious problem: how to deal with large quantities of end-of-life or obsolete electronic equipment. While there are various technical challenges for electronic product recovery and recycling, this research focuses on printed circuit boards (PCBs) or printed wiring boards (PWBs). PCBs are primary components in many electronic products built for both military and commercial applications. Due to their complex construction and the consequent complicated mixture of materials, PCB recycling presents a serious challenge to today's industry. The rich content of precious metals provides a strong economic justification for materials recovery and recycling. On the other hand, large amounts of toxic components and fiber-reinforced polymers create difficulties for recycling and adverse environmental impact.

Professor Carol Korzeniewski of Texas Tech University is funded by the Analytical and Surface Chemistry Program to study oxidation pathways of methanol and related small molecules on electrodes, which constitute fundamental steps in fuel cells. Bulk and graphite-supported nanoparticles that contain platinum and platinum-group metals will serve as substrates. The reactions will be studied by vibrational spectroscopy, scanning force microscopy and Monte Carlo simulations. The objective is to identify steps that limit current flow, an understanding of which can help to improve electric power generation. Different molecular behaviors are observed on bulk and nanoparticle materials. This research could lead to a molecular understanding of this paradox.

Fuel cells are an exciting growing technology based on an electrochemical device that combines hydrogen fuel and oxygen from the air to produce electricity, heat and water. Fuel cells operate without combustion, so they are virtually pollution free. Research is needed to overcome some of the problems and to further develop this technology.

With support from the Chemistry Research Instrumentation and Facilities: Multiuser program (CRIF:MU), the Department of Chemistry at Texas Tech University will acquire a 10.8 TeraFlop, parallel computing cluster. The computing cluster will be used by researchers to study a number of problems in the chemical sciences, including (a) the hydrolysis of cellulose as an efficient route to biofuels; (b) simulations of electrochemical surface reactions; (c) accurate quantum dynamical calculations for chemical reactions; (d) the role of non-adiabaticity in the chemistry of the early universe; (e) dynamics of protonated peptide ion surface-induced decomposition; and (f) studies of electronically non-adiabatic dynamics using a coherent-states model. The computing cluster will be used in a number of ongoing activities carried out by the department targeted to groups which have been traditionally underrepresented in the sciences. Software will be developed and freely-disseminated. Cyberinfrastructure will enable researchers at other schools (i.e. Eastern New Mexico University, and University of Texas, Permian Basin) to use this equipment.

Modern computer infrastructure allows chemists to do some experiments , virtually, without the need to use chemical reagents. In addition, checked against experiment, new, more accurate theoretical methods may be developed. In tandem with experiment, computations allow chemists to examine, in detail beyond that of current experimental methods, the molecular ballet that takes place in complicated chemical processes. The infrastructure made available with this grant will be used in teaching and training a broad range of young scientists in computational chemistry -- from high school, all the way through the post-graduate level.

"This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5)."

Professor Carol Korzeniewski of Texas Tech University is supported by the Analytical and Surface Chemistry Program in the Division of Chemistry to investigate the processes that limit charge transfer during the conversion of chemical bond energy into electricity in electrocatalytic reactions. The proposed research is focused on two areas: catalysis of reactions relevant to fuel cells, and the impact of Nafion on catalysis as it adsorbs to noble metal catalyst sites. SEIRAS will be used to characterize the species at and near the surface; voltammetry will be used to examine the kinetics of the reactions of interest; and modeling will integrate this information to develop detailed and fundamental understanding of the dynamics of the surface reactions. The new knowledge gained on interfacial charge transfer processes would have broad applications in energy conversion processes such as fuel cells, corrosion, adhesion and signal transduction in electrical sensors. The educational activities involve the training of graduate and undergraduate students, and outreach plans towards women and girls at K-12 through the Texas Tech University sponsored science and engineering outreach programs.

With this award from the Chemistry Research Instrumentation and Facilities: Multi-user (CRIF:MU) program, Professor Carol Korzeniewski and colleagues Christopher Bradley, Dominick Casadonte, Michael Mayer and William Nes from Texas Tech University will acquire a cyber-enabled premium-shielded 400 MHz NMR spectrometer. The proposal is aimed at enhancing research training and education at all levels, especially in areas of study such as (a) development of cobalt catalysts for hydrocarbon activation/functionalization, (b) photochemical studies of metal phenanthroline-based molecular assemblies, (c) synthetic, structural and reactivity studies on zwitterionic metal silanides, siloxides and silane dendrimers, (d) development of neuropeptide mimics and enantioselective synthesis using chiral N-phosphonyl imines, (e) preparation of mechanically interlocked polymeric materials, and (f) studies to unravel sterol biosynthesis.

Nuclear Magnetic Resonance (NMR) spectroscopy is one of the most powerful tools available to chemists for the elucidation of the structure of molecules. It is used to identify unknown substances, to follow the progress of chemical reactions, to characterize specific arrangements of atoms within molecules, and to study the dynamics of interactions between molecules in solids and in solution. Access to state-of-the-art NMR spectrometers is essential to carry out frontier chemistry related research and to train students in modern research techniques. The results from these NMR studies will have an impact on organic, materials, electronics and bioorganic chemistry research. The resources will be used not only for research activities but also for research training of undergraduate and graduate students including those from underrepresented groups.

Electrochemical systems, such as fuel cells and electrolyzers, have a central role in the development of electric vehicles and systems for renewable energy conversion, and recent revolutionary impact on specialty chemical synthesis. In striving to improve the selectivity and energy efficiency of electrochemical systems, techniques to directly study the reactions at electrodes under operating conditions have long been sought for the rapid diagnosis of the limiting processes. This project will advance in-situ characterization methods that profile the distribution of chemical components within membranes and membrane-catalyst components at high resolution. The project outcomes will aid the design of next-generation membranes for electrochemical systems. The project will also engage students across all levels in research and integrate research with mentoring, education and outreach. The project will strengthen institutional outreach activities targeting female and underrepresented minority students in middle schools and high schools. The investigators will enrich their programs with the addition of peer-mentoring components to the Mother-Daughter program (TTU and Lubbock American Association of University Women) and the Curie Club (U Utah) that aim to increase retention of students in STEM. By applying their professional scientific experiences, the PIs are helping to encourage retention of STEM students and impact underserved groups in their regions.

In the study of bipolar membranes, the phenomena of ion-depletion, water accumulation, and water-splitting will be investigated under the applied voltages and transmembrane pH gradients that are of practical interest for catalytic reaction optimization. A membrane system, based on spin-castable ion-exchange polymers and deuterium isotope labeled mobile ions, will be constructed for neutron reflectometry measurements to enable attainment of spatial resolution approaching 1 nm in profiling the interface separating anion- and cation-exchange phases. Results will provide benchmarks for furthering the mass transport and kinetic models that guide strategies for improving device energy conversion efficiency. In another project example involving biocatalytic membrane applications, a multi-catalytic cascade utilizing nitrogenase enzymes for N2 reduction will be assembled through the use of redox polymers that facilitate electron transfer and ?wiring? of enzymes within the electrode assembly. In-situ spatial mapping of membrane composition will guide modifications, based on pendant phenathiazine moieties, for the dual role of electron transport mediation to nitrogenase and O2 scavenging in a separate, enzyme-free electrode capping layer. The capping layer will mitigate nitrogenase sensitivity toward O2 and support efforts toward the important goal of constructing ambient temperature N2 to NH3 conversion platforms capable of operation in air. All neutron reflectometry measurements will be conducted in collaboration with the National Institute of Standards and Technology (NIST) Center for Neutron Research.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.