物理化学学报 >> 2017, Vol. 33 >> Issue (12): 2454-2462.doi: 10.3866/PKU.WHXB201706092

论文 上一篇    下一篇

利用强度调制光电流/光电压谱研究碳点/KOH电解液界面的动力学行为

桑丽霞*(),蔺佳,葛昊,雷蕾   

  • 收稿日期:2017-05-08 发布日期:2017-09-05
  • 通讯作者: 桑丽霞 E-mail:sanglixia@bjut.edu.cn
  • 基金资助:
    国家自然科学基金(51376013)

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 E-mail:sanglixia@bjut.edu.cn
  • Supported by:
    the National Natural Science Foundation of China(51376013)

摘要:

通过强度调制光电流谱(IMPS)和强度调制光电压谱(IMVS)技术研究在光电分解水制氢体系中碳点光阳极与KOH电解液界面的动力学行为。结果表明,光强在30-90 mW·cm-2范围内,界面的电子传输时间(τd)、电子寿命(τn)、电子扩散系数(Dn)、电子扩散长度(Ln)均没有变化;当光强增加到110和130 mW·cm-2时,τdτn延长,而Dn减小。实验表明,不同于TiO2/电解液等界面,碳点光电极/电解液界面中碳点电极存在的缺陷少,因此电子主要以无陷阱限制扩散方式传输为主。且在30-130 mW·cm-2的光强范围内,与τdτn相关的载流子收集效率(ηcc)相近。

关键词: 碳点, 光电制氢, 界面动力学, IMPS, IMVS

Abstract:

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

MSC2000: 

  • O649