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Chemistry and Industry of Forest Products ›› 2023, Vol. 43 ›› Issue (2): 116-126.doi: 10.3969/j.issn.0253-2417.2023.02.015

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Preparation of Porous Graphite Carbon Nitride and Its Visible Light Catalytic Conversion of Lignin

Chunyu REN1, Xiangyu LIN2, Zhuomin WANG1, He LIU1,*()   

  1. 1. Institute of Chemical Industry of Forest Products, CAF; Key Lab. of Biomass Energy and Material, Jiangsu Province; Key Lab. of Chemical Engineering of Forest Products, National Forestry and Grassland Administration; National Engineering Research Center of Low-Carbon Processing and Utilization of Forest Biomass; Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, Nanjing 210042, China
    2. College of ChemicalEngineering, Nanjing Forestry University, Nanjing 210037, China
  • Received:2022-01-09 Online:2023-04-28 Published:2023-04-26
  • Contact: He LIU E-mail:liuhe_caf@163.com

Abstract:

Porous graphitic carbon nitride(mpg-CN) material with large surface area(126.6 m2/g) was successfully prepared by removing silica from a graphitic carbon nitride(g-C3N4)/silica composite, where the latter was synthesized using urea and tetraethyl orthosilicate(TEOS) as precursors through thermal polycondensation. Nitrogen adsorption-desorption isotherm, SEM, TEM, XRD, ultraviolet-visible diffuse reflectance spectroscopy(UV-Vis DRS), photoluminescence spectroscopy(PL) and electrochemical impedance spectroscopy(EIS) were used to analyze the internal structure, physical morphology, crystalline form and photoelectrical properties of the catalyst. The results showed that the introduction of TEOS had almost no effect on the crystal structure and band gap of the catalyst, while it could increase the specific surface area, pore volume and pore size of mpg-CN, thus providing more active sites. mpg-CN had lower photogenerated carrier recombination rate, higher photogenerated carrier separation efficiency and mobility, which was beneficial to the improvement of photocatalytic activity. To test the photocatalytic activity and product selectivity of the catalyst with different atmospheres and solvents conditions, a lignin model compound 1(2-phenoxy-1-phenylethanol) was used as the substrate. The results showed that under the conditions of catalyst mpg-CN, illumination, O2 atmosphere and solvent of CH3CN for 7.5 h, the conversion rate of 2-phenoxy-1-phenylethanol can reach 98.06%, and the selectivity of C-C bond cleavage was 91.79%. The result of the capture experiment proved that the photo-generated hole(h+) was the main active substance in the induced reactions. mpg-CN also had good stability and recycling performance, and the conversion rate of model compound 1 was 93%-98% when it was recycled for 1-8 times. Furthermore, the catalyst also showed a high conversion rate of 93.18% for the photocatalytic conversion of complex dimer lignin model compound 1b(1-(3-methoxyphenyl)-2-(2-methoxyphenoxy)-propane-1-diol).

Key words: porous g-C3N4, visible light catalysis, lignin, model compounds

CLC Number: