A comparative assessment of carbonaceous electrodes with diverse interfacial properties for H2O2 electrogeneration

Abstract

AbstractBACKGROUNDThe present study investigates the in situ electrogeneration of H2O2 by the 2e− oxygen reduction reaction in an electrochemical flow cell using three commercially available cathodic electrode materials with different interfacial properties; that is, activated carbon felt (ACF), non‐activated carbon felt (NACF) and gas diffusion electrode (GDE).RESULTSExperiments were first performed to optimize the operating parameters and to determine the yield of H2O2 electrosynthesis. The estimated maximum yield of ~40% was achieved with the NACF electrode after 30 min of operation. Furthermore, the performance of the electrodes was investigated in two scenarios, namely (i) under conditions with O2‐saturated electrolyte and (ii) under continuous air supply, to study the differences in O2 distribution within the electrode material as a function of its interfacial properties. The maximum H2O2 concentration for the first scenario was 3.86 mg L−1 after 60 min of operation, which was obtained with the NACF electrode. In contrast, in the second scenario, H2O2 electrogeneration was significantly increased for all three electrodes, with the GDE exhibiting the best performance, at 43.3 mg L−1 after 60 min of operation.CONCLUSIONSThe properties of the electrode material play a decisive role in H2O2 electrogeneration. The hydrophilicity of the electrode is very important when O2 is dissolved in the electrolyte. Hydrophobicity is preferable when gaseous O2 is applied to the electrode as a three‐phase interface is formed, which favors the transfer/penetration of O2. The pore size of the electrode is of crucial importance, as mesoporous materials facilitate the distribution of gaseous O2 in the electrode body. © 2024 Society of Chemical Industry (SCI).