Acta Phys. -Chim. Sin. ›› 2017, Vol. 33 ›› Issue (12): 2454-2462.doi: 10.3866/PKU.WHXB201706092

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Dynamic Analysis of Carbon Dots/KOH Electrolyte Interface by IMPS/IMVS

Li-Xia SANG*(),Jia LIN,Hao GE,Lei LEI   

  • Received:2017-05-08 Published:2017-09-05
  • Contact: Li-Xia SANG
  • Supported by:
    the National Natural Science Foundation of China(51376013)


The dynamic behaviors at the interface of carbon dots and KOH electrolyte were studied using intensity-modulated photocurrent spectroscopy (IMPS) and intensity-modulated photovoltage spectroscopy (IMVS) in the photoelectrochemical hydrogen production from water splitting. The results show that the kinetic parameters like electron transport time (τd), electron diffusion coefficient (Dn), electron lifetime (τn), and electron diffusion length (Ln) remain unchanged in the light intensity range of 30-90 mW·cm-2. When the light intensity increases to 110 and 130 mW·cm-2, τd and τn increase, while Dn decreases. It is indicated that the photogenerated electrons are mainly transported in the trap-free limited diffusion mode at the electrode/electrolyte interface due to the presence of few defects in carbon dots, which is different from the mode of transport at the semiconductor TiO2/electrolyte interface. Moreover, the photocarrier collection efficiencies (ηcc) associated with the electron transport time and the electron lifetime are similar for light intensity of 30-130 mW·cm-2.

Key words: Carbon dots, Photoelectrochemical hydrogen production, Interface dynamic, IMPS, IMVS


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