Pressure intensified HO evolution from OER and electrolysis desulfurization

To strengthen the formation of Hydroxyl radical (HO) on anode, pressurized water electrolysis under constant temperature were carried out in this work. The HO formation was verified by electrochemistry-electron spin resonance (ESR) and bauxite desulfurization in the same pressurized reactor with dif...

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Bibliographic Details
Published in:Electrochimica acta 2019-09, Vol.318, p.202-210
Main Authors: Zhang, Tong, Zhou, Yujian, Hu, Yingnan, Wang, Zhi, Liu, Junhao, Qian, Guoyu, Gong, Xuzhong
Format: Article
Language:English
Subjects:
Anodes
Bauxite
Bayer process
Desulfurization
Desulfurizing
Electrochemistry
Electrolysis
Electron paramagnetic resonance
Electron spin
HO
Hydroxyl radicals
Mass transfer
OER
Oxygen evolution reactions
Pressure
Pressurized water
Spin resonance
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Summary:To strengthen the formation of Hydroxyl radical (HO) on anode, pressurized water electrolysis under constant temperature were carried out in this work. The HO formation was verified by electrochemistry-electron spin resonance (ESR) and bauxite desulfurization in the same pressurized reactor with different cell designs. With increasing pressure, the current density was increased. However, the equilibrium potential of anode and the initial potential of oxygen evolution reaction (OER) were negative shifted with increasing pressure. Results revealed that pressure promoted the early steps of OER but inhibited subsequent transformation. The apparent transfer coefficient of the anode (ba and bc) further proved that the pressure play a positive role on the OER reserve reaction and promoted the formation of HO. Rct and Rs were all decreased with increasing pressure, demonstrating that pressure improved the mass transfer and reaction of the OER. The electrolysis desulfurization and ESR experiments have clearly supported the positive role of pressure on strengthening the HO formation. From electrolysis with 0.1 MPa, HO signal was detected by ESR when constant potential was 0.8 V on anode, while the signal arose at 0.7 V under 1.0 MPa, indicating that HO was formed in advance under pressure.
ISSN:0013-4686
1873-3859
DOI:10.1016/j.electacta.2019.06.080