The research in the Neidig group focuses on the generation of new fundamental insight into structure, bonding and mechanism in homogeneous, heterogeneous and biological non-precious metal catalysts. Motivation for this research arises from the need for new catalytic routes for alternative energy applications (i.e. biomass, solar, fuel cells) as well as sustainable catalysts that are cheaper and more environmentally benign. Non-precious metal catalysts have a tremendous potential to address these significant challenges. For example, iron displays a rich redox chemistry and is inexpensive, widely available and generally non-toxic. However, in many cases, development of non-precious metal catalysts has been limited by a lack of fundamental understanding of catalyst site structure, bonding, reactivity and catalytic mechanism. A significant challenge central to this limitation is often the presence of paramagnetic starting materials or the generation of paramagnetic species along the reaction coordinate.
Central to the research in the Neidig group is the utiliztion of a physical-inorganic approach to investigate non-precious metal catalyst systems, with an emphasis on iron catalysis. Electron paramagnetic resonance (EPR) and variable-temperature, variable-field (VTVH) magnetic circular dichroism (MCD) spectroscopies combined with electronic absorption provide detailed information on the electronic structure of the metal catalysts, including metal-ligand binding and metal site geometry. The combination of these techniques, where appropriate, with resonance Raman, X-ray absorption methods and density function theory calculations yields a detailed description of the iron site structure and bonding. Importantly, this general approach is equally applicable to both ground-state structures and trapped intermediates, providing the opportunity for detailed studies on species generated along the reaction coordinate.
Current areas of interest in the group in non-precious metal catalysis include the following: (1) structure-property relationships in non-precious metal organometallics, (2) catalysis for energy applications focusing on catalytic site elucidation and mechanistic insight in non-precious metal fuel cell catalysts for oxygen reduction, and (3) electronic structure, bonding and mechanism in biologically relevant reduction catalysis including small molecule N2 fixation. The results of these research efforts will provide the necessary foundation to further advance the design and development of non-precious metal catalysts to solve key challenges in sustainable chemistry, alternative energy and non-petroleum based feedstock conversion.