A parallel-plate electrochemical microreactor for the continuous production of hydrogen peroxide

Apostolova, Desislava (author), Bardarov, Ivo (author), Tjell, Anders Ø. (author), Gričar, Ema (author), Starin, Mark (author), Farinazzo Bergamo Dias Martins, Pedro (author), Nosan, Miha (author), Mayr, T. (author), Strmčnik, Dušan (author), Plazl, Igor (author), Genorio, Boštjan (author)

This study presents a comprehensive evaluation of a microfluidic electrochemical system for the controlled generation and detection of hydrogen peroxide (H$_2$O$_2$). The integrated microreactor with a three-electrode configuration in combination with optical sensors enabled real-time monitoring of dissolved oxygen and H$_2$O$_2$ concentrations during chronoamperometric operation. Glassy carbon (GC) electrodes exhibited high selectivity toward the two-electron oxygen reduction reaction (2e$^−$ ORR), a key requirement for efficient H$_2$O$_2$ electrosynthesis. Cyclic voltammetry (CV), rotating ring-disk electrode (RRDE) analyses and electrochemical testing in real system identified 0.4 V vs. RHE as the optimal working potential. Flow rate experiments revealed a decline in H$_2$O$_2$ production with increasing flow rates, consistent with electrical charge measurements and oxygen consumption data. A mathematical model, validated with experimental data, reliably predicted H$_2$O$_2$ outlet concentration as a function of flow rate (residence time). The model captured the interplay between mass transport and surface electrocatalytic reactions and enabled the identification of an optimal operating window (25–50 μL min$^{−1}$), supporting model-based reaction optimization. Post-experiment surface characterization using SEM-EDS, XPS, and μ-FTIR revealed increased oxygen-containing functional groups on the GC working electrode, indicating surface oxidation that may enhance catalytic performance. Overall, this system offers a scalable, sustainable platform for on-demand H$_2$O$_2$ production, supporting cleaner, decentralized electrochemical synthesis with reduced environmental impact and greater adaptability for modern industrial applications.

• Language: English
• Keywords: electrosynthesis, hydrogen peroxide, two-electron oxygen reduction reaction, carbon electrocatalysts, electrochemical microreactor, continuous flow microreactor
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: FKKT - Faculty of Chemistry and Chemical Technology
• Publication status: Published
• Publication version: Version of Record
• Year: 2025
• Number of pages: 11 str.
• Numbering: Vol. 525, art. 170301
• PID: 20.500.12556/RUL-175775
• UDC: 661.491.087
• ISSN on article: 1385-8947
• DOI: 10.1016/j.cej.2025.170301
• COBISS.SI-ID: 256282115
• Publication date in RUL: 07.11.2025

Record is a part of a journal

• Title: Chemical engineering journal
• Shortened title: Chem. eng. j.
• Publisher: Elsevier Sequoia
• ISSN: 1385-8947
• COBISS.SI-ID: 2110998

Licences

• License: CC BY-NC 4.0, Creative Commons Attribution-NonCommercial 4.0 International
• Link: http://creativecommons.org/licenses/by-nc/4.0/
• Description: A creative commons license that bans commercial use, but the users don’t have to license their derivative works on the same terms.

Secondary language

• Language: Slovenian
• Keywords: elektrosinteza, vodikov peroksid, dvoelektronska reakcija redukcije kisika, ogljikovi elektrokatalizatorji, elektrokemijski mikroreaktor, pretočni mikroreaktor