In Situ Fluorescence Imaging of Electrode-Structure-Dependent Dissolved Oxygen Distributions During Electrocatalytic H₂O₂ Production.

Authors

Jiawang He, Hao Lin, Dongxu Chen, Ling Lu, Lele Cui, Tianle Zhou, Lianyu Li, Huaiyi Xu, Xueru Niu, Lin Lin, Jingyu Xi, Dongzhi Li, Le Liu

Published in

Small (Weinheim an der Bergstrasse, Germany). Pages e75713. Sep 09, 2026. Epub Sep 09, 2026.

Abstract

Hydrogen peroxide (H₂O₂) is an important green oxidant, and its electrosynthesis via the two-electron oxygen reduction reaction (2e^- ORR) provides a sustainable alternative to the conventional anthraquinone process. However, H₂O₂ production is governed not only by catalyst properties but also by the local dissolved oxygen (DO) distribution at the electrode-electrolyte interface, which remains difficult to resolve using conventional bulk measurements. Herein, we develop an in situ fluorescence imaging system based on the oxygen-dependent quenching of tris(2,2-bipyridine) ruthenium(II) (Ru(bpy)₃ ²⁺), enabling quantitative visualization of fluorescence-derived DO variations in the near-electrode region during electrocatalytic H₂O₂ production. A reliable calibration correlates fluorescence intensity with DO concentration, while a DnCNN-based denoising strategy suppresses fluorescence noise, improves the detection limit, and preserves pixel-scale spatial information. Using this system, current-dependent near-interface fluorescence-derived DO variation is monitored, revealing rapid initial DO redistribution followed by a quasi-steady transport-reaction balance. Comparative studies of carbon paper and gas diffusion electrodes reveal distinct electrode-architecture-associated near-interface DO responses, suggesting differences in local oxygen accessibility and interfacial transport behavior. Spatially resolved analysis of laser-perforated porous electrodes reveals heterogeneous DO distributions in non-pore regions, pore interiors, and pore edges. This work provides a quantitative in situ approach for probing electrode-structure-dependent DO distributions during H₂O₂ electrosynthesis.

PMID:
42714394
Bibliographic data and abstract were imported from PubMed on 09 Sep 2026.

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