Tandem Electro- and Thermo-Catalytic Continuous Reactor for Hydrogen Peroxide-Mediated Cyclohexene Epoxidation

Electrocatalysis offers a sustainable and safe alternative to fossil fuel-based chemical production by converting carbon feedstocks into value-added chemicals using renewable electricity. One promising target is the production of epoxides. Epoxides are key chemical intermediates to produce epoxies, pharmaceuticals, and textiles, yet electrochemical approaches to their synthesis remain limited by poor selectivity and low activity. Direct electrooxidation, in which electrons transfer from the electrode directly to the organic substrate, suffers from high overpotential and numerous by-products. As an alternative, indirect electrooxidation via redox mediators such as hydrogen peroxide can enhance selectivity and activity towards the desired epoxide product, while maintaining industrially relevant current densities. In this approach, the electrochemically generated mediator subsequently reacts thermocatalytically to form the epoxide. Integrating electrocatalytic and thermocatalytic processes offers an industrially relevant path to improve performance, while mitigating safety and environmental risks. Herein, we present a hydrogen-peroxide-mediated cyclohexene epoxidation system that integrates a dual-membrane electrode assembly (MEA) solid-electrolyte electrolyzer with a downstream thermocatalytic flow reactor. The indirect electrooxidation strategy first produces hydrogen peroxide, which oxidizes cyclohexene downstream in a biphasic, thermocatalytic reactor. We evaluate the resiliency of the MEA towards continuous recycle operation, evaluating the impact of temperature modification, Na 2 WO 4 catalyst addition, and solid electrolyte variability. This work highlights the operational flexibility of tandem electro- and thermo-catalytic reactor designs, especially for future integration into existing industrial thermochemical processes. Insight from this work supports the development of indirect electrooxidation platforms for scalable and flexible industrial applications. Figure 1