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Dennis H. EvansProfessor of Chemistry dhevans@email.arizona.edu Carl S. Marvel Laboratories 436 Phone: (520) 626-0318 Fax: (520) 621-8407 |
Honors
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Education and Appointments
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Research Interests
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Research Summary | |
| Elucidation of the Mechanisms of Complex, Multi-step Electrode Reactions of Organic and Organometallic Compounds including the Evaluation of the Catalytic Efficiency of Synthetic Diiron Hydrogenase Mimics The principal objective of research in this group is the elucidation of the mechanisms of complex, multi-step electrode reactions of organic and organometallic compounds. The results of this research are relevant not only in the areas of organic and inorganic chemistry, but also find applications in chemical analysis, electroorganic synthesis, pollution control, electrocatalysis, batteries and fuel cells. A full understanding of an electrode reaction must include a complete description of its component steps. Thus, our work includes studies of the factors controlling the rates of simple electron-transfer reactions occurring at electrode surfaces as well as the electron-transfer reactions in solution near the electrode that involve the various species in the overall mechanism (reactants, intermediates, products). Other component reactions are of a more chemical nature. They may be as simple as an isomerization or conformational change of the reactant or an intermediate. However, bonds may also be formed (dimerization, protonation) or broken (loss of an atom or functional group) and these steps combine with the electron-transfer reactions to make up the overall process. We have recently initiated studies of the electrocatalysis of the reduction of weak acids to produce dihydrogen. These synthetic catalysts are mimics of the active sites of diiron hydrogenase enzymes. The mechanisms of the electrocatalysis have not been fully elucidated and such studies are underway in order to obtain mechanistic understanding that will guide the synthesis of new catalysts. The techniques that are employed include all of the methods of electroanalytical
chemistry with particular emphasis on the use of microelectrodes to facilitate
fast measurements. The group is especially well known for the application
of fast scan cyclic voltammetry to electroanalytical problems. New capabilities
recently acquired include instrumentation for electrochemical impedance
spectroscopy and the electrochemical quartz crystal microbalance. The standard
chromatographic and spectroscopic methods are employed for the characterization
of the starting materials and products of electrode reactions.
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Selected Publications | |
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