Bioinspired Coordination Complexes and Polymers for Energy Applications
Research in the Marinescu group focuses on the development of novel catalytic systems for efficient solar-to-fuel technologies. Inspired by biological systems, we design molecular catalysts that involve hydrogen bonding networks capable of small molecule activation through multiple proton and electron transfers. We have shown that cobalt complexes with pendant secondary amine (NH) moieties act as highly efficient electrocatalysts for the reduction of CO2 to CO, in comparison to the alkylated versions. Through synthetic and electrochemical studies of a series of aminopyridine complexes with zero to four pendant secondary amines, we have demonstrated that the rate of catalysis is proportional with the number of pendant NH moieties. Experiment and theory suggest that the pendant NH groups do not directly transfer protons to CO2, but instead bind acid molecules from solution, leading to the formation of a hydrogen-bonding network intermediate that enables direct proton transfer from acid to the activated CO2 substrate.
We also explore the immobilization of metal complexes via metal-organic frameworks (MOFs). We have demonstrated the successful integration of metal dithiolene units into one and two-dimensional frameworks by using dinucleating and trinucleating thiolate-based ligand scaffolds. The developed metal dithiolene frameworks display high activity for the electrocatalytic HER in acidic aqueous media. The HER performance of the MOF-based electrocatalysts was investigated, to understand the charge transfer properties of the constructed MOF/electrode architecture. Density functional theory calculations were applied to understand the structure of the MOF and its mechanistic pathways for the HER. We expect the design principles discovered in these studies to have a profound impact towards the development of advanced materials and sustainable technologies.
Hosted by Professor Mark Lipke