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Study on Influence Factors of H 2 O 2 Generation Efficiency on Both Cathode and Anode in a Diaphragm-Free Bath.

Tian TianZhaohui WangKun LiHonglei JinYang TangYanzhi SunPingyu WanYong Mei Chen
Published in: Materials (Basel, Switzerland) (2024)
Electrosynthesis of H 2 O 2 via both pathways of anodic two-electron water oxidation reaction (2e-WOR) and cathodic two-electron oxygen reduction reaction (2e-ORR) in a diaphragm-free bath can not only improve the generation rate and Faraday efficiency (FE), but also simplify the structure of the electrolysis bath and reduce the energy consumption. The factors that may affect the efficiency of H 2 O 2 generation in coupled electrolytic systems have been systematically investigated. A piece of fluorine-doped tin oxide (FTO) electrode was used as the anode, and in this study, its catalytic performance for 2e-WOR in Na 2 CO 3 /NaHCO 3 and NaOH solutions was compared. Based on kinetic views, the generation rate of H 2 O 2 via 2e-WOR, the self-decomposition, and the oxidative decomposition rate of the generated H 2 O 2 during electrolysis in carbonate electrolytes were investigated. Furthermore, by choosing polyethylene oxide-modified carbon nanotubes (PEO-CNTs) as the catalyst for 2e-ORR and using its loaded electrode as the cathode, the coupled electrolytic systems for H 2 O 2 generation were set up in a diaphragm bath and in a diaphragm-free bath. It was found that the generated H 2 O 2 in the electrolyte diffuses and causes oxidative decomposition on the anode, which is the main influent factor on the accumulated concentration in H 2 O 2 in a diaphragm-free bath.
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