NSF-BSF: Towards a Molecular Understanding of Dynamic Active Sites in Advanced Alkaline Water Oxidation Catalysts

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With the support of the Chemical Catalysis program in the Division of Chemistry, Professor Shannon Boettcher of University of Oregon, Eugene is studying the chemistry of catalytic materials for high-efficiency, low-cost generation of green hydrogen from electrically driven water splitting. This research is motivated in part by a grand challenge in the field known as the hydrogen shot, with the target of reaching the production of hydrogen fuel at $1 per 1 kg within one decade. Green hydrogen is obtained as the product of one-half of the overall water splitting reaction. The other half, water oxidation, limits the overall efficiency of hydrogen generation and must be accelerated by earth-abundant catalysts to improve rates and lower costs. Boettcher’s group has developed several catalysts based on nickel, iron, and cobalt with efficient water oxidation ability that are promising for hydrogen technologies. With this grant, his group will study with molecular precision the underlying chemical principles and structures that dictate the high performance of these catalysts and whether these chemical principles hold under industry-relevant conditions. This will be done by leveraging academic partnerships that facilitate rapid access to advanced surface characterization and computational techniques, and practical feedback from industrial collaborators. In addition to supporting work which will have a high impact on the field of catalysis, this grant will also provide key training to graduate and undergraduate students soon to enter the burgeoning renewable energy workforce, facilitate the continuation of educational outreach among students from the middle school to undergraduate level.Under this award, Professor Shannon Boettcher and his research team are studying fundamental chemical descriptors for advanced alkaline water-oxidation catalysts. Water oxidation is characterized by slow kinetics and represents a key constraint in the performance of large-scale hydrogen production through water electrolysis. This oxidation reaction typically occurs on the surface of heterogeneous oxides/oxyhydroxides that are poorly defined, which makes relating structural, compositional, and electronic features to observed activity difficult. Fundamental catalysis science discoveries can address these challenging relations and, importantly, translate learned principles into improved technology for alkaline hydrogen production. With this grant, Prof. Boettcher and his team are building a fundamental understanding of active-site generation, retention, and loss for record-activity earth-abundant Fe-Ni/Co oxyhydroxides. Specifically, they will (1) study how the structure and properties of newly proposed surface Fe-oxo cluster active sites drive high activity in these transition-metal oxyhydroxides; (2) develop chemical descriptors to explain surface restructuring and activation of crystalline oxides (vs. amorphous oxides) for the oxygen evolution reaction (OER); and (3) understand if and how dynamic catalyst surfaces and Fe-based active sites drive record OER catalysis in high-temperature concentrated electrolyte conditions. The work seeks to build a more complete, temperature-dependent, thermodynamic and kinetic understanding of the materials and surface processes central to water oxidation at industrially relevant conditions. These aims will be studied through a combination of computation and experiment, with a significant focus on experiments conducted under operating conditions. Collaborative computational efforts by Prof. Maytal Caspary-Toroker at the Technion in Haifa, Israel, funded separately by the U.S.-Israel Binational Science Foundation, is expected to provide new and more accurate approaches to modeling the thermodynamics and kinetic processes in these complex oxyhydroxides.This collaborative US/Israel project is supported by the US National Science Foundation and the Israel Binational Science Foundation.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.