First-‐Row Transition Metal Coordination Compounds for the Electrocatalytic Generation of Hydrogen from Organic and Aqueous Solutions
Date Thesis Awarded
Honors Thesis -- Access Restricted On-Campus Only
Bachelors of Science (BS)
William R. McNamara
Robert D. Pike
Carey K. Bagdassarian
Kurt E. Williamson
The development of stable proton reduction catalysts is imperative due to their importance as a source of a carbon-neutral fuel. A cobalt-salen complex with electron withdrawing groups was synthesized. This complex generated protons from organic solutions at a 190 mV overpotential with a kobs of 42000 M-2s-1, and a corresponding turnover frequency of 420 s-1. This is one of the lowest overpotentials reported for a cobalt proton reduction catalyst. While insoluble in water, an experiment where water was added to an electrochemical cell showed a 20% increase in catalytic activity. This indicates that cobalt-salen complexes could be highly active in aqueous solutions.
Developing first row transition metal complexes for electro- and photocatalytic hydrogen evolution is of great interest. A photocatalyst for proton reduction could be incorporated into an artificial photosynthesis device to generate hydrogen gas as a solar fuel. Nickel was complexed with the H3ttfasbz ligand, which is known to be redox active.35 In order to assess its catalytic ability electrochemical tests, including proton concentration experiments, and catalyst concentration experiments were performed. These tests showed the nickel complex to be highly active for hydrogen reduction at a cathodic potential (-1.37 V vs. SCE). Due to the high overpotential of this complex, it was integrated into a photocatalytic system with fluorescein as a chromophore.
Crossland, Patrick M., "First-‐Row Transition Metal Coordination Compounds for the Electrocatalytic Generation of Hydrogen from Organic and Aqueous Solutions" (2015). Undergraduate Honors Theses. William & Mary. Paper 233.
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