Structure and Reactivity of Transient Species in Homogeneous Catalytic Water Splitting and CO2 Reduction Using Cryogenic Ion Spectroscopy
Technical Report,01 Feb 2013,30 Apr 2018
Yale University New Haven United States
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Under this grant, we have designed, commissioned and exploited new and general experimental methods for the purpose of identifying the reaction pathways that govern the catalytic transformations of small molecules like H2O, N2 and CO2. We accomplished this by trapping key fragile chemical species deep in the catalytic cycle that have been calculated or inferred to play an important role in chemical transformation but have never been isolated. Our approach involved the development of a new type of instrument that combines high resolution mass spectrometry, cryogenic ion processing, and laser photofragmentation spectroscopy. One major accomplishment from this effort is the successful application of the new methods to determine how the degree of CO2 activation by a homogeneous Ni coordination compound depends on oxidation state and ligand structure. Another important result is the determination of the mode of activation of an Ir-based water splitting catalyst in which unsuspected ligand oxidation of the monometallic precursor yields the active bimetallic catalyst. Because mobile protons are usually involved in covalent bond formation of activated species, we have developed a theoretical framework that extracts structural information from the diffuse vibrational bands that are the usual signatures of charge translocation through hydrogen bonded networks.
- Atomic and Molecular Physics and Spectroscopy