氮化碳空心微球的结构调控及其光催化氧化还原性能
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摘要
以乙腈为溶剂,通过改变前驱物三聚氰氯和二聚氰胺的比例来调控氮化碳(CN)空心球.采用X-射线衍射(XRD)、扫描电子显微镜(SEM)、傅里叶红外(FTIR)和紫外可见漫反射(UV-Vis DRS)对材料的晶相、形貌以及光吸收性质进行了详细分析.结果表明,通过改变前驱物的比例可以对CN空心球进行调控.以氙灯为光源,通过降解MO和还原Cr(VI)对调控的CN空心球活性进行测试;通过改变Cr(VI)溶液的pH值来改善还原Cr(VI)的效率并研究了其机理.同时对甲基橙(MO)的光催化降解和Cr(VI)的光催化还原之间的相互作用进行了考察,适当降低Cr(VI)溶液pH值能够提高其光催化还原率.通过自由基捕获实验得知在CN光催化还原Cr(VI)过程中起主要作用的是e~-和·O_2~-.在Cr(VI)/MO/CN空心球体系中,Cr(VI)和MO对双方的光催化过程都有促进作用.一定浓度的MO加入后,对降解MO和还原Cr(VI)都具有促进作用.
CN hollow spheres were controlled by changing the ratio of precursor cyanuric chloride and dicyandiamide in acetonitrile as solvent. The crystal phases, morphology, and optical absorption properties of the samples were characterized by X-ray diffraction(XRD), scanning electron microscopy(SEM), Fourier transform infrared(FTIR) and UV-Vis diffuse reflectance(UV-Vis DRS) analysis. The results show that the control of CN hollow spheres is changed by changing the ratio of precursor. Using xenon lamp as the light source, the controlled CN hollow sphere activity was tested by degradation of MO and reduction of Cr(VI). At the same time, the efficiency of Cr(VI) reduction was improved by changing the pH value of Cr(VI) solution, and the mechanism was studied. The interaction between photocatalytic degradation of MO and photocatalytic reduction of Cr(VI) was investigated. It is possible to improve the photocatalytic reduction rate of Cr(VI) when pH value is appropriately reduced. It is found that the main role in the process of photocatalytic reduction of Cr(VI) is played by e~-and ·O_2~-. In the Cr(VI)/MO/CN hollow sphere system, Cr(VI) and MO promote both photocatalytic processes. We found that after the addition of certain concentrations of MO, the degradation of MO and reduction of Cr(VI) have a catalytic effect.
CN hollow spheres were controlled by changing the ratio of precursor cyanuric chloride and dicyandiamide in acetonitrile as solvent. The crystal phases, morphology, and optical absorption properties of the samples were characterized by X-ray diffraction(XRD), scanning electron microscopy(SEM), Fourier transform infrared(FTIR) and UV-Vis diffuse reflectance(UV-Vis DRS) analysis. The results show that the control of CN hollow spheres is changed by changing the ratio of precursor. Using xenon lamp as the light source, the controlled CN hollow sphere activity was tested by degradation of MO and reduction of Cr(VI). At the same time, the efficiency of Cr(VI) reduction was improved by changing the pH value of Cr(VI) solution, and the mechanism was studied. The interaction between photocatalytic degradation of MO and photocatalytic reduction of Cr(VI) was investigated. It is possible to improve the photocatalytic reduction rate of Cr(VI) when pH value is appropriately reduced. It is found that the main role in the process of photocatalytic reduction of Cr(VI) is played by e~-and ·O_2~-. In the Cr(VI)/MO/CN hollow sphere system, Cr(VI) and MO promote both photocatalytic processes. We found that after the addition of certain concentrations of MO, the degradation of MO and reduction of Cr(VI) have a catalytic effect.
引文
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[ 3 ] TORRES-MARíINE L M, MOCTEZUMA E, RUIZ-GóMEZ M A, et al. Sol-gel synthesis of Sm2InTaO7 and its photocatalyticactivity on degradation of crystal violet dye and reduction of Cr(VI) ions [J]. Research on Chemical Intermediates, 2013, 39(4): 1533-1544. DOI:10.1007/s11164-012-0618-6.
[ 4 ] 单冰倩,杨宏训,张雷. 一种由Keggin型多酸和铜配合物构筑的难溶性三维杂化材料的合成、结构及光催化性能[J]. 江苏科技大学学报(自然科学版),2016, 30(5):498-502. DOI:10.3969/j.issn.1673-4807.2016.05.016SHAN Bingqian, YANG Hongxun, ZHANG Lei. Syntjesis, structure and photocatalytic property of an insoluble 3D hybrid material based on Kegginpolyoxometalates and CuI-pyrazine coordination compounds[J]. Journal of Jiangsu University of Science and Technology (Natural Science Edition), 2016, 30(5):498-502.DOI:10.3969/j.issn.1673-4807.2016.05.016 (in Chinese)
[ 5 ] JI D L, ZHU J Z, JI M, et al. Enhanced photocatalytic reduction of Cr(VI) by manganese-doped anatase titanium dioxide [J]. Research on Chemical Intermediates, 2016, 42(6):5413-5429. DOI:10.1007/s11164-015-2375-9.
[ 6 ] JIN Z, ZHANG Y X, MENGA F L, et al. Facile synthesis of porous single crystalline ZnOnano-plates and their application in photocatalytic reduction of Cr(VI) in the presence of phenol [J]. Journal of Hazardous Materials, 2014, 276(9): 400-407. DOI: 10.1016/j.jhazmat.2014.05.059.
[ 7 ] LIU F H, YU J, TU G Y, et al. Carbon nitride coupled Ti-SBA15 catalyst for visible-light-driven photocatalytic reduction of Cr (VI) and the synergistic oxidation ofphenol [J].Applied Catalysis B: Environmental, 2017, 201: 1-11. DOI: 10.1016/j.apcatb.2016.08.001
[ 8 ] KURTIKYAN T S, EKSUZYAN S R, HAYRAPETYAN V A, et al. Nitric oxide dioxygenation reaction by oxy-coboglobin models: in-situ low-temperature FTIR characterization of coordinated peroxynitrite [J]. Journal of American Chemical Society, 2012, 134(33):13861-13870. DOI:10.1021/ja305774v.
[ 9 ] WANG Y X, WANG H, CHEN F Y, et al. Facile synthesis of oxygen doped carbon nitride hollow microsphereforphotocatalysis [J].Applied Catalysis B: Environmental, 2017, 206: 417-425. DOI:10.1016/j.apcatb.2017.01.041.
[10] ZANG Y C, ZHANG Q, SHI Q W, et al. Acid-treated g-C3N4 with improved photocatalytic performance in the reduction of aqueous Cr(VI) under visible-light [J].Separation and Purification Technology, 2015, 142: 251-257. DOI: 10.1016/j.seppur.2014.12.041.
[11] JIN Z, ZHANG Y X, MeENGA F L, et al. Facile synthesis of porous single crystalline ZnOnano-plates and their application in photocatalytic reduction of Cr(VI) in the presence of phenol [J]. Journal of Hazardous Materials, 2014, 276(9): 400-407. DOI: 10.1016/j.jhazmat.2014.05.059.