Insight into the Enhanced Photocatalytic Activity of Potassium and Iodine Codoped Graphitic Carbon Nitride Photocatalysts
Insight into the Enhanced Photocatalytic Activity of Potassium and Iodine Codoped Graphitic Carbon Nitride Photocatalysts
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DOI：
10.1021/acs.jpcc.6b06921
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发表时间：
2016-11-10
影响因子：
3.7
通讯作者：
Fang, Xiaoming
中科院分区：
文献类型：
--
作者：
Guo, Yarong;Chen, Tianxiang;Fang, Xiaoming
采用热聚合法制备了钾碘共掺杂的石墨氮化碳（CN-KI）光催化剂。采用多种技术表征CN-KI光催化剂，并阐明K和I共掺杂的机理。与CN相比，CN-KI的光吸收边发生了红移，电子自旋共振分析表明，CN-KI的可见光响应放大主要源于I的掺杂。然后，光致发光光谱显示，与原始CN相比，CN-KI中光生载流子的复合被延迟，并且电化学阻抗谱测量表明，K掺杂导致载流子复合的减少，因为将K掺杂到CN网络中提高了电荷传输效率。结果表明，当KI的质量分数达到最佳时，K和I共掺杂的g-C3 N4样品由于K和I掺杂的协同效应而表现出比仅掺杂K或I的样品更好的上级光催化活性。本工作为开发高性能的g-C3 N4光催化剂提供了重要的理论依据。
Potassium and iodine codoped graphitic carbon nitride (CN-KI) photocatalysts were prepared via thermal polymerization of a mixture prepared by dissolving dicyandiamide into a KI solution. Several techniques were employed to characterize the CN-KI photocatalysts and elucidate the mechanisms of the K and I codoping. Compared to pristine CN, CN-KI exhibited a red shift in optical absorption edge, and the electron spin resonance analysis revealed that the enlargement of the visible light response mostly originated from I doping. Then, photoluminescence spectra showed that recombination of photogenerated carriers in CN-KI was retarded compared to that in pristine CN, and electrochemical impedance spectroscopy measurements suggested that the decrease in carrier recombination resulted from K doping because the doping with K into the CN network improved the charge transportation efficiency. Consequently, the K and I codoped g-C3N4 sample with an optimal mass fraction of KI exhibited superior photocatalytic activity over those doped with only K or I owing to the synergistic effect of the K and I doping. This work might shed light on cation anion codoping for developing high-performance g-C3N4 photocatalysts.