Zero-gap Bipolar Membrane Electrolysis for Chemical Production

The goal of this project is to turn two types of waste into two useful products at the same time. The first type of waste is nitrate, which comes from things like farm runoff. This nitrate will be changed into ammonia, which can be used as fertilizer. The second waste is glycerol, which is a leftover material from making biofuels. It will be changed into formate, which is another useful chemical. To do this, both waste streams will go through special chemical reactions using electricity. To make these reactions happen in a way that uses as little energy as possible, many parts of the system must work together. A novel idea in this project is to use a bipolar membrane. This membrane helps electric current flow between the two sides of the system, while also letting each side run under different, best-suited conditions. By letting each reaction happen under the best conditions, the whole system should work more efficiently. This project will also help scientists better understand how the parts of the system work, including the electrodes (cathode and anode) and the bipolar membrane. There are no reported studies that incorporate bipolar membranes (BPMs) in electrolyzers for the simultaneous reduction of nitrate under acidic conditions and organic oxidation under alkaline conditions. The project will begin by investigating the individual components in isolation. An important question is whether the ionomers used to bind electrocatalysts to a conductive support influence the electrocatalytic rate and mechanism. Understanding these interactions is crucial due to the close contact of the cation exchange layer (CEL) and anion exchange layer (AEL) polymers and electrocatalysts in a zero-gap BPM electrolyzer. This study aims to deepen the scientific community’s understanding of how ionomers affect electrocatalyst performance for these reactions. Additionally, investigating the transport of reactants, products, protons, and hydroxide through the CEL, AEL, BPM, and various interfaces is essential for creating efficient electrolyzer systems. Integration of BPMs into electrolyzers will enable simultaneous reduction of molecules under acidic conditions and oxidation of molecules under alkaline conditions, opening possibilities for a variety of chemical transformations. Furthermore, this project will help cultivate interdisciplinary skills among participating PhD students, fostering expertise in both experimental and computational aspects of electrochemistry and membranes. 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.