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林产化学与工业 ›› 2023, Vol. 43 ›› Issue (2): 116-126.doi: 10.3969/j.issn.0253-2417.2023.02.015

• 研究报告 • 上一篇    下一篇

多孔石墨相氮化碳的制备及其可见光催化木质素转化研究

任春雨1, 林详宇2, 王倬敏1, 刘鹤1,*()   

  1. 1. 中国林业科学研究院 林产化学工业研究所; 江苏省生物质能源与材料重点实验室; 国家林业和草原局林产化学工程重点实验室; 林木生物质低碳高效利用国家工程研究中心; 江苏省林业资源高效加工利用协同创新中心, 江苏 南京 210042
    2. 南京林业大学 化学工程学院, 江苏 南京 210037
  • 收稿日期:2022-01-09 出版日期:2023-04-28 发布日期:2023-04-26
  • 通讯作者: 刘鹤 E-mail:liuhe_caf@163.com
  • 作者简介:刘鹤, 研究员, 博士生导师, 研究领域为林业生物质资源的化学利用研究; E-mail: liuhe_caf@163.com
    任春雨(1992-), 女, 河南开封人, 硕士生, 主要从事木质素光催化转化制备高价值芳香化合物的研究

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

摘要:

以尿素和正硅酸乙酯(TEOS)为前驱体, 经热缩聚得到石墨相氮化碳(g-C3N4)/SiO2复合材料, 除去SiO2后, 制备了具有较大比表面积(126.6 m2/g)的多孔石墨相氮化碳(mpg-CN)材料。采用N2吸附-脱附等温线、SEM、TEM、XRD、紫外-可见漫反射光谱(UV-Vis DRS)、光致发光光谱(PL)和电化学阻抗谱(EIS)对催化剂的内部结构、微观形貌、晶体结构和光电性质进行了表征, 结果表明:TEOS的引入对催化剂的晶型结构和带隙几乎没有影响, 但可以使mpg-CN的比表面积、孔容和孔径有所增加, 从而提供更多的反应活性位点;mpg-CN具有较低的光生载流子复合率, 较高的光生载流子分离效率和迁移率, 有利于促进光催化活性的提高。以木质素模型化合物2-苯氧基-1-苯乙醇(1)为底物, 对催化剂在不同气氛和溶剂条件下的光催化活性和产物选择性进行了研究,结果表明:在催化剂为mpg-CN、光照、O2气氛和溶剂CH3CN的条件下反应7.5 h, 化合物1的转化率可达98.06%, C—C断裂选择性为91.79%, 捕获实验的结果证明了光生空穴(h+)是诱导反应发生的主要活性物种, mpg-CN还具有良好的稳定性和循环使用性能, 循环使用1~8次时模型化合物1的转化率为93%~98%;同时该催化剂对复杂二聚体木质素模型化合物1-(3, 4-二甲氧基苯基)-2-(2-甲氧基苯氧基)-丙烷-1, 3-二醇(1b)的光催化转化也显示出93.18%的高转化率。

关键词: 多孔g-C3N4, 可见光催化, 木质素, 模型化合物

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

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