CAS: Design and Mechanistic Understanding of Emerging Metal Chalcogenide Electrocatalysts for Selective Two-Electron Oxygen Reduction

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With the support of the Chemical Catalysis Program in the Division of Chemistry, Professors Song Jin and J. R. Schmidt of the University of Wisconsin-Madison will design and study new selective and stable electrocatalysts to produce hydrogen peroxide (H2O2) from oxygen using electricity. Hydrogen peroxide is a green chemical oxidant with many industrial and environmental applications. In contrast to current centralized chemical production of H2O2, electrochemical production of H2O2 by direct reduction of oxygen would reduce cost and energy consumption, and enable distributed production using renewable electricity. To this end, there have been significant recent advances in the development of electrocatalysts for H2O2 electrosynthesis. Nonetheless, the performance of these catalysts and their long-term stability still need improvement. This collaborative project will build on the team’s prior accomplishments to design, investigate and then enhance a series of new metal chalcogenide electrocatalysts. The scientific understanding of selective oxygen reduction using emerging metal chalcogenide electrocatalysts will enable new approaches for the generation of H2O2 for myriad applications in environment, including water treatment, and in sustainability, particularly for alternative chemical production, for example, with H2O2 as oxidant. Concerted efforts on educational outreach to K-12 students and fostering a more diverse scientific community will also be undertaken.In this project, the collaborative Jin/Schmidt team at the University of Wisconsin-Madison will combine theory and experiment to design and investigate emerging metal chalcogenide electrocatalysts and the factors that govern their catalytic stability, activity, selectivity for 2e- electroreduction of oxygen to produce H2O2 in acidic and neutral solutions. Such selective 2e- oxygen reduction reaction (ORR) electrocatalysts can facilitate decentralized electrochemical production of H2O2, an environmentally benign oxidant with diverse applications. Specifically, new layered metal chalcogenide electrocatalysts will be investigated experimentally and theoretically to achieve better selectivity, activity and stability for 2e– ORR, especially in neutral solutions. Density functional theory calculations to develop microkinetic models will be directly connected with multiple types of operando studies with the aim of identifying key reaction intermediates and understanding catalytic mechanism. Systematic electrochemical studies and molecular dynamics simulations followed by in situ measurements will be undertaken to help elucidate the role of cations and solvents in enhancing the electrocatalysts. This project has the potential to facilitate the efficient decentralized electrochemical production of H2O2 and in so doing have broad scientific impact in environmental and sustainability chemistry. The mechanistic insights and operando approaches developed herein will also lay the groundwork for addressing increasingly complex challenges in selective electrocatalysis using more diverse metal compounds.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.