CAS: Collaborative Research: New Hybrid Catalysts for Sustainable Cross-Coupling Reactions: Using Atomic Layer Deposition to Immobilize and Enhance Molecular Catalysts

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Chemicals like plastics and medicines are essential to modern life. However, large-scale chemical production can require large amounts of energy and can create toxic waste. Catalysts can reduce the energy needed to produce chemicals, reduce waste, and provide large cost savings for chemical manufacturers. The goal of this project is to develop new catalysts to make specific chemical products while also reducing both energy usage and the creation of toxic waste. This research is developing advanced catalysts that are both selective and easily recovered for repeated use. Further, these catalysts are being used in non-toxic and non-corrosive liquids, like water. Thus, these catalysts make chemical production safer for workers and reduce hazards to surrounding communities and the environment. This research program is studying how to design these catalysts for use in chemical reactions that are otherwise difficult to achieve under less hazardous and energy efficient conditions. This program pairs Dr. Aaron Vannucci at the University of South Carolina, an expert in chemical catalysis, with Dr. Mark Losego at the Georgia Institute of Technology, an expert in materials synthesis. Ph.D. students funded by this project are being jointly trained in both fields. This exchange of skills is expanding the scientific training for students in both groups and will impact future students at both universities. Dr. Vannucci is actively running outreach programs to train high school teachers in the chemical sciences. Dr. Losego is directing a materials analysis facility run by and for undergraduate students. These programs promote interest, education, and training in STEM fields at multiple levels. Skills exchanged during this project are being used to further enhance these hands-on STEM training programs. With joint funding from the Chemical Catalysis Program and the Established Program to Stimulate Competitive Research, Dr. Aaron Vannucci from the University of South Carolina and Dr. Mark Losego from the Georgia Institute of Technology are collaboratively developing knowledge about new hybrid catalysts that immobilize non-precious metal molecular catalysts on oxide nanoparticle supports with nano-scale metal oxide over-layers deposited via atomic layer deposition (ALD). These molecular/heterogeneous catalysts have already shown excellent recyclability for Suzuki cross-coupling reactions via simple filtration and washing. Physicochemical studies are being conducted to understand not only the ability for ALD layers to physically stabilize the catalyst molecules on the particle surfaces but also the synergistic chemical interactions between the ALD metal oxide over-layer and molecular catalyst that lead to enhanced catalytic activity. Specifically, the investigators are developing strategies using ALD processing and chemistry to control the local geometric and chemical environment around the active site to achieve difficult C(sp3)-C(sp3) and stereoconvergent coupling reactions relevant to medical research and drug discovery. These hybrid catalysts adhere to many green chemistry principles including the utilization of non-noble metals, operation in non-corrosive, aqueous solvents, and ease in separation and recyclability. This program also supports extended student and investigator exchanges at the collaborative institutions to cross-train the Ph.D. students in orthogonal scientific disciplines of chemical catalysis and vapor deposition processing. These knowledge and skill sets are being institutionalized in each lab group and broadly impact current and future generations of students. During these exchanges the visiting investigators are developing programs to further enhance existing outreach and training programs that support hands-on undergraduate education and high school teacher training.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.