Preparation of potassium ion doped graphite carbon nitride via molten salt method and its photocatalytic mineralization ability of organic pollutants

HU Shao-zheng; LI Wei; GU Gui-zhou; YUAN Xing-zhou; LIANG Fei-xue; WU Guang

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China Environmental Science ›› 2020, Vol. 40 ›› Issue (7) : 3106-3113.

Preparation of potassium ion doped graphite carbon nitride via molten salt method and its photocatalytic mineralization ability of organic pollutants

HU Shao-zheng¹, LI Wei¹, GU Gui-zhou¹, YUAN Xing-zhou¹, LIANG Fei-xue¹, WU Guang²

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Abstract

A band gap-tunable potassium doped graphitic carbon nitride (g-C₃N₄) with enhanced RhB degradation ability was prepared via molten salt method. X-ray diffraction (XRD), UV-Vis spectroscopy, X-ray photoelectron spectroscopy (XPS), N₂ adsorption, Photoluminescence (PL) and Electrochemical impedance spectra (EIS) were used to characterize the prepared catalysts. The addition of potassium inhibited the crystal growth of graphitic carbon nitride, enhanced the surface area and increased the separation rate of photogenerated electrons and holes. In addition, by controlling the potassium ion doping amount, the CB and VB potentials of graphitic carbon nitride can be adjusted within a certain range, so that the oxidative degradation reaction of organic pollutants changes from single oxidant (·O₂^-) reaction to double oxidant (·OH and·O₂^-) reaction, leading to the promoted degradation and mineralization ability. The RhB degradation rate constant of as-prepared potassium ion doped catalyst arrived 0.022min^-1, which is 5 times higher than that of neat g-C₃N₄. Moreover, the degradation rate of the as-prepared catalyst to other organic pollutants, such as methyl blue and phenol, was also significantly improved by tuning the energy level.

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energy level control / g-C₃N₄ / K⁺ doping / molten salt method / photocatalysis

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HU Shao-zheng, LI Wei, GU Gui-zhou, YUAN Xing-zhou, LIANG Fei-xue, WU Guang. Preparation of potassium ion doped graphite carbon nitride via molten salt method and its photocatalytic mineralization ability of organic pollutants[J]. China Environmental Science. 2020, 40(7): 3106-3113

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