NSF-DFG Echem: Strategies to Overcome Contemporary Limitations of Reductive Electrosynthetic Conversions in Aqueous Media

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In this project, we introduce highly disruptive concepts to address the severe shortcomings of hydrogen evolution and cathodic corrosion in reductive organic electrosynthesis. By focusing on cationic hydrogen inhibitors and unconventional cathode materials, we will efficiently address both hindering problems and the broader implementation of this inherently green technique is possible. Both individual concepts reside beyond the current forefront in the organic electrosynthesis by themselves. However, the discrete complementary approaches can be fruitfully combined which will have wide ramifications in chemistry, engineering, and chemical industry.Our aim with the novel cationic hydrogen inhibitors is to selectively increase the overvoltage for hydrogen evolution reaction which allows us to perform reactions that are inaccessible by the current state-of-the-art methods. The beauty of our concept lies in the fact that we can use these cationic hydrogen inhibitors either as additives or (electro)graft them to suitable electrode materials. This will grant as high flexibility as also the organic cationic inhibitors can be tailored for specific requirements. We will focus also on chiral additives and magnetic fields. With the former, we employ chiral cationic inhibitors that can transfer sterogenic information to various substrates while suppressing the detrimental hydrogen evolution and cathodic corrosion. With the latter, the cumulative effects of electric and magnetic fields will lead to a tighter decoration of the cathode which further accentuates the beneficial effects of the cationic hydrogen inhibitors. The stated shortcomings can be tackled from a different perspective by using unconventional materials such as Ga/In mixtures, ternary alloys of zinc and lead, bismuth, and bismuth alloys as cathodes. They excel in many aspects. For example, while exhibiting high hydrogen overpotentials, some of them have higher biocompatibilities, or increased resistances towards cathodic corrosion than the contemporary alternatives often used in reductive electrochemistry. In all cases, their performance in organic electrosynthesis has not yet been fully elucidated and it is plausible that doing so will open new avenues for organic electrosynthesis. Both conceptually new strategies presented herein overcome the current limitations in reductive electrosynthesis for a broad range of applications. Even on their own merit, they will advance the field far off from the current state-of-the-art. An enormous and immediate boost in innovation from either of these concepts in both academia and chemical industry is conceivable, and by combining these two distinct strategies, further amplification of their high impact is envisioned.