Carbon quantum dots based charge bridge between photoanode and electrocatalysts for efficiency water oxidation

Due to its earth abundant and excellent stability, metal oxide semiconductor attracts great attention in photoelectrochemical water splitting. However, its performance is restricted due to the high recombination rate of electron-hole pairs even modified with electrocatalysts. In this work, carbon qu...

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Bibliographic Details
Published in:Electrochimica acta 2018-05, Vol.273, p.208-215
Main Authors: Jiang, Xiao, Zhang, Zemin, Mei, Junfeng, Han, Dongyan, Xie, Mingzheng, Wang, Fangcong, Xie, Erqing, Han, Weihua
Format: Article
Language:English
Subjects:
Carbon
Carbon quantum dots
Charge efficiency
Charge separation efficiency
Charge transfer
Cobalt
Electric bridges
Electric contacts
Electrocatalysis
Electrocatalysts
Electrodes
Hematite
Metal oxide semiconductors
Oxidation
Photoanodes
Photoelectric effect
Photoelectric emission
Photovoltaic cells
Quantum dots
Silver chloride
Surface photovoltage spectrum
Water
Water oxidation
Water splitting
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Summary:Due to its earth abundant and excellent stability, metal oxide semiconductor attracts great attention in photoelectrochemical water splitting. However, its performance is restricted due to the high recombination rate of electron-hole pairs even modified with electrocatalysts. In this work, carbon quantum dots are studied as the charge bridge to boost the charge transfer kinetics of cobalt phosphate (Co-Pi)/Fe2O3 photoanode at the photoanode/electrocatalyst interface. Our results show that carbon quantum dots significantly improve the charge transfer and charge separation efficiency of Co-Pi/Fe2O3 photoanode. The photocurrent is substantially enhanced to 4.9 mA/cm2 at 0.6 V (vs. Ag/AgCl) which is much higher than Co-Pi/Fe2O3 photoanode 3.7 mA/cm2 in the same situation. These results provide a strategy to improve photoanode performance by facilitating the electrical contact at the photoanode/electrocatalyst interface with carbon quantum dots. [Display omitted] •The charge transfer between electrocatalysts and photoanode is improved.•CQDs was found to increase the charge separation efficiency evidenced by surface photovoltage spectra.•CQDs as a charge bridge enhance water oxidation by promoting hole separation and transfer.
ISSN:0013-4686
1873-3859
DOI:10.1016/j.electacta.2018.04.052