2025/04/28 by Hübner, Jessica Liane, Ruland, Gina, Pietschmann, Florian +3
#500 Naturwissenschaften und Mathematik::540 Chemie::540 Chemie und zugeordnete Wissenschaften #cation enhancement effect #electric double layer #hydrogen peroxide #oxygen reduction reaction
paper · doi:10.14279/depositonce-23530
Hydrogen peroxide (H2O2) is an important green industrial oxidant. The two-electron oxygen reduction reaction (2e− ORR) represents a promising emerging process for sustainable H2O2 production, leveraging renewable energy sources. For industrial applications, 2e− ORR electrolyzers must operate at high current densities, achieve high product selectivities, and utilize robust, cost-effective catalyst materials, thus making carbon-based catalysts highly sought after. This study focuses on drastically improving the performance of commercial gas diffusion electrodes (GDEs) for the 2e− ORR by optimizing the electrolyte composition, paving the way for a cost-effective large-scale production of H2O2. We demonstrate that while leveraging the cation enhancement effect of otherwise electrocatalytically inactive alkali metal cations (AMCs), the performance of commercial carbon GDEs surpasses that of previously published 2e− ORR electrolyzers. Particular focus was placed on the role of competing and subsequent reactions, such as the hydrogen evolution reaction (HER), the hydrogen peroxide reduction reaction (HPRR), and the H2O2 auto-disproportionation. For the first time, the complex interplay of these reactions was continuously monitored using an online H2O2 detection setup, employing both single-pass and closed-loop modes.