Unveiling the influence of organic environments on H2O2 electrogeneration with gas diffusion electrodes in flow cells.
SANTOS, Géssica de Oliveira Santiago; MARIN, Beatriz Tavoloni; PARRA, William Santacruz; MOTHEO, Artur de Jesus; NASCIMENTO, Otaciro Rangel; RODRIGO, Manuel Andrés; LANZA, Marcos Roberto de Vasconcelos.
SANTOS, Géssica de Oliveira Santiago; MARIN, Beatriz Tavoloni; PARRA, William Santacruz; MOTHEO, Artur de Jesus; NASCIMENTO, Otaciro Rangel; RODRIGO, Manuel Andrés; LANZA, Marcos Roberto de Vasconcelos.
Abstract: This study presents a novel approach for the electrogeneration of H2O2 in methanol and aqueous-methanol mixtures (30% and 50% v/v methanol), all containing 0.015 mol L-1 H2SO4. Electrochemical characterization via rotating ring-disk electrode (RRDE) revealed activity of methanol and its mixtures for both carbon blacks as electrocatalyst: Printex® L6 (PL6C) and Vulcan XC-72R. H2O2 production was further evaluated in a custom-designed 3D-printed flow cell equipped with a Printex® L6 carbon gas diffusion electrode (PL6C-GDE), operated in both divided and undivided configurations. In the divided cell, aqueous media achieved the highest Faradaic efficiency (FE), whereas methanol-based systems showed lower FE and increased energy consumption. Notably, in the undivided configuration, methanol performance improved significantly, approaching the FE observed for aqueous electrolyte in the divided setup. This enhancement is attributed to reduced overpotentials, minimized interelectrode distance, and suppression of hydrogen evolution and anodic scavenging reactions. Conversely, in aqueous media, FE decreased in the undivided cell due to H2O2 degradation at the anode. Electron paramagnetic resonance (EPR) spectroscopy with spin trapping identified distinct radical species in the aqueous electrolyte and methanol, indicating solvent-dependent ORR pathways. The detection of unique intermediates such as ?CH2OH underscores the mechanistic divergence in organic media. Collectively, these findings demonstrate the feasibility of in situ H2O2 generation in organic and mixed-solvent systems, offering new opportunities for electrochemical oxidation processes and green synthetic applications.
@article={003283959,author = {SANTOS, Géssica de Oliveira Santiago; MARIN, Beatriz Tavoloni; PARRA, William Santacruz; MOTHEO, Artur de Jesus; NASCIMENTO, Otaciro Rangel; RODRIGO, Manuel Andrés; LANZA, Marcos Roberto de Vasconcelos.},title={Unveiling the influence of organic environments on H2O2 electrogeneration with gas diffusion electrodes in flow cells},journal={Electrochimica Acta},note={v. 551, p. 148112-1-148112-13},year={2026}}