Investigating apparent links between water oxidation and oxidative dissolution

Many processes that use electricity to drive chemical production require a material that oxidizes water to oxygen gas. This reaction generates a highly corrosive environment, which can dissolve the expensive materials that perform the reaction. New electrocatalysts are designed around two main goals: energy efficiency and durability. However, these metrics are often at odds with one another, and designing for durability is challenging. This project will investigate how energy efficiency and durability are interlinked. It will also examine when they diverge to help in the search for new materials. The project will utilize well-defined surfaces to quantify dissolution and water oxidation rates. It will also characterize how the material surfaces change with time. The findings will improve our ability to predict and improve both durability and catalytic efficiency. The project will enable the use of less expensive materials for electricity-driven chemical processes and will train students in science and engineering research. This project will develop fundamental, quantitative insight into the competitive rates of oxidative dissolution and oxygen evolution over oxide electrocatalysts. Model catalyst surfaces will be fabricated with molecular beam epitaxy. This will control the crystallographic facet and surface site density. It will also interrogate the catalyst electronic structure over a broad compositional space. Metal-oxygen covalency will be tailored with strain and octahedral distortion. Defect concentration will be manipulated via physical approaches. The project will consider rutile oxide alloys, moving towards earth abundant catalysts for acidic oxidation reactions. The research will examine dynamic vs steady state dissolution and activity behavior. This will help develop a quantitative understanding of accelerated degradation testing and catalyst lifetime assessment. The evolution of these properties with time/cycle number will also inform a mechanistic understanding of dynamic stabilization. Findings will provide quantitative insight into the development and translation of accelerated stability tests. This will shorten the time between development and deployment of new catalyst chemistries and electrocatalytic devices, which broadly contribute to efficient chemical production and energy conversion/storage. 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.