常压条件下NaOH剥离g-C_3N_4及其光催化性能研究
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摘要
通过热聚合法制备了块状g-C_3N_4,并利用不同浓度的NaOH对块状g-C_3N_4进行常压剥离处理,获得了大比表面积、疏松多孔的g-C_3N_4。对样品进行了XRD、SEM、TEM、BET、PL、FT-IR、UV-Vis光谱多项表征,并进行了降解罗丹明B光催化性能测试。结果显示,随着NaOH溶液浓度的增加,g-C_3N_4疏松程度增加,经过浓度为0.3 mol/L的NaOH处理的g-C_3N_4层间氢键破坏程度大,层内的结构也遭到一定程度的破坏,比表面积明显增大,是块状g-C_3N_4的5.5倍。较大的比表面积有效地增加了对罗丹明B的吸附性,同时经过0.3 mol/L的NaOH处理的g-C_3N_4电子与空穴的复合速率降低,吸附和光催化协同效应使0.3 mol/L NaOH处理过的g-C_3N_4光催化降解罗丹明B的效率较块状的g-C_3N_4有较大程度的提高。
In order to obtain loose porous g-C_3N_4 with large specific surface area, bulk g-C_3N_4 was prepared by thermal polymerization and treated with different concentrations of NaOH solution under normal pressure. The samples were characterized by XRD, SEM, TEM, BET, PL, FT-IR and UV-Vis spectra, and the photocatalytic performance of degraded rhodamine B was tested. The results showed that the looseness of g-C_3N_4 increased with the increase of alkali concentration. The hydrogen bond between the layers of g-C_3N_4 treated with 0.3 mol/L NaOH was destroyed, and the structure in the layer was also damaged to some extent. The specific surface area increased significantly, which was 5.5 times that of bulk g-C_3N_4. The larger specific surface area effectively increased the adsorption performance of rhodamine B, while the recombination rate electrons and holes in g-C_3N_4 treated by 0.3 mol/L NaOH were reduced. The synergistic effect of adsorption and photocatalysis made the efficiency of photocatalytic degradation of rhodamine B by 0.3 mol/L NaOH treated g-C_3N_4 improve significantly compared to bulk g-C_3N_4.
In order to obtain loose porous g-C_3N_4 with large specific surface area, bulk g-C_3N_4 was prepared by thermal polymerization and treated with different concentrations of NaOH solution under normal pressure. The samples were characterized by XRD, SEM, TEM, BET, PL, FT-IR and UV-Vis spectra, and the photocatalytic performance of degraded rhodamine B was tested. The results showed that the looseness of g-C_3N_4 increased with the increase of alkali concentration. The hydrogen bond between the layers of g-C_3N_4 treated with 0.3 mol/L NaOH was destroyed, and the structure in the layer was also damaged to some extent. The specific surface area increased significantly, which was 5.5 times that of bulk g-C_3N_4. The larger specific surface area effectively increased the adsorption performance of rhodamine B, while the recombination rate electrons and holes in g-C_3N_4 treated by 0.3 mol/L NaOH were reduced. The synergistic effect of adsorption and photocatalysis made the efficiency of photocatalytic degradation of rhodamine B by 0.3 mol/L NaOH treated g-C_3N_4 improve significantly compared to bulk g-C_3N_4.
引文
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[26] Wang Z, Huo Y, Fan Y, et al. Facile synthesis of carbon-rich g-C3N4 by copolymerization of urea and tetracyanoethylene for photocatalytic degradation of Orange II[J]. Journal of Photochemistry and Photobiology A: Chemistry, 2018, 358: 61-69.
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[28] 中国污水处理工程网.罗丹明B废水光催化处理技术[EB/OL](2015-6-28).http://www.dowater.com/jishu/2015-06-28/352561/.html.
[2] Li H, Wu X, Yin S, et al. Effect of rutile TiO2 on the photocatalytic performance of g-C3N4/brookite-TiO2-xNy photocatalyst for NO decomposition[J]. Applied Surface Science, 2017, 392:531-539.
[3] Fan C, Feng Q, Xu G, et al. Enhanced photocatalytic performances of ultrafine g-C3N4 nanosheets obtained by gaseous stripping with wet nitrogen[J]. Applied Surface Science, 2018, 427: 730-738.
[4] Mamba G, Mishra A K. Graphitic carbon nitride (g-C3N4) nanocomposites: a new and exciting generation of visible light driven photocatalysts for environmental pollution remediation[J]. Applied Catalysis B: Environmental, 2016, 198: 347-377.
[5] Akhundi A, Habibi-Yangjeh A. Novel magnetic g-C3N4/Fe3O4/AgCl nanocomposites: Facile and large-scale preparation and highly efficient photocatalytic activities under visible-light irradiation[J]. Materials Science in Semiconductor Processing, 2015, 39:162-171.
[6] Li J, Zhang M, Li X, et al. Effect of the calcination temperature on the visible light photocatalytic activity of direct contact Z-scheme g-C3N4-TiO2 heterojunction[J]. Applied Catalysis B: Environmental, 2017, 212:106-114.
[7] Ding W, Liu S, He Z. One-step synthesis of graphitic carbon nitride nanosheets for efficient catalysis of phenol removal under visible light[J]. Chinese Journal of Catalysis, 2017, 38(10):1711-1718.
[8] Chidhambaram N, Ravichandran K. Single step transformation of urea into metal-free g-C3N4 nanoflakes for visible light photocatalytic applications[J]. Materials Letters, 2017, 207:44-48.
[9] Praus P, Svoboda L, Ritz M, et al. Graphitic carbon nitride: synthesis, characterization and photocatalytic decomposition of nitrous oxide[J]. Materials Chemistry and Physics, 2017, 193:438-446.
[10] Zhao H, Yu H, Quan X, et al. Fabrication of atomic single layer graphitic-C3N4 and its high performance of photocatalytic disinfection under visible light irradiation[J]. Applied Catalysis B: Environmental, 2014, 152:46-50.
[11] Zhao H, Yu H, Quan X, et al. Atomic single layer graphitic-C3N4: fabrication and its high photocatalytic performance under visible light irradiation[J]. Rsc Advances, 2014, 4(2):624-628.
[12] Niu P, Zhang L, Liu G, et al. Graphene-like carbon nitride nanosheets for improved photocatalytic activities[J]. Advanced Functional Materials, 2012, 22(22):4763-4770.
[13] Liang Q, Li Z, Huang Z H, et al. Holey graphitic carbon nitride nanosheets with carbon vacancies for highly improved photocatalytic hydrogen production[J]. Advanced Functional Materials, 2015, 25(44):6885-6892.
[14] Xu Y, Xie M, Huang S, et al. High yield synthesis of nano-size g-C3N4 derivatives by a dissolve-regrowth method with enhanced photocatalytic ability[J]. Rsc Advances, 2015, 5(33):26281-26290.
[15] Sano T, Tsutsui S, Koike K, et al. Activation of graphitic carbon nitride (g-C3N4) by alkaline hydrothermal treatment for photocatalytic NO oxidation in gas phase[J]. Journal of Materials Chemistry A, 2013, 1(21): 6489-6496.
[16] Xu Y S, Zhang L L, Yin M H, et al. Ultrathin g-C3N4 films supported on attapulgite nanofibers with enhanced photocatalytic performance[J]. Applied Surface Science, 2018, 440: 170-176.
[17] Zhang Y, Jin Z, Wang G. Charge transfer behaviors over MOF-5@ g-C3N4 with NixMo1-xS2 modification[J]. International Journal of Hydrogen Energy, 2018, 43(21): 9914-9923.
[18] Cheng J, Hu Z, Lyu K, et al. Drastic promoting the visible photoreactivity of layered carbon nitride by polymerization of dicyandiamide at high pressure[J]. Applied Catalysis B: Environmental, 2018, 232: 330-339.
[19] Shi A, Li H, Yin S, et al. Effect of conjugation degree and delocalized π-system on the photocatalytic activity of single layer g-C3N4[J]. Applied Catalysis B: Environmental, 2017, 218: 137-146.
[20] Cheng F X, Exfoliation of graphitic carbon nitride and its photocatalytic application[D]. Hangzhou: Zhejiang Sci-Tech University, 2015(in Chinese).程福星. 石墨相氮化碳的剥离及其在光催化中的应用[D].杭州: 浙江理工大学, 2015.
[21] Yang S, Gong Y, Zhang J, et al. Exfoliated graphitic carbon nitride nanosheets as efficient catalysts for hydrogen evolution under visible light[J]. Advanced Materials, 2013, 25(17): 2452-2456.
[22] Niu P, Zhang L, Liu G, et al. Graphene-like carbon nitride nanosheets for improved photocatalytic activities[J]. Advanced Functional Materials, 2012, 22(22): 4763-4770.
[23] Khan A, Alam U, Raza W, et al. One-pot, self-assembled hydrothermal synthesis of 3D flower-like CuS/g-C3N4 composite with enhanced photocatalytic activity under visible-light irradiation[J]. Journal of Physics and Chemistry of Solids, 2018, 115: 59-68.
[24] Bicalho H A, Lopez J L, Binatti I, et al. Facile synthesis of highly dispersed Fe(Ⅱ)-doped g-C3N4 and its application in Fenton-like catalysis[J]. Molecular Catalysis, 2017, 435: 156-165.
[25] Xu Y S, Zhang L L, Yin M H, et al. Ultrathin g-C3N4 films supported on Attapulgite nanofibers with enhanced photocatalytic performance[J]. Applied Surface Science, 2018, 440: 170-176.
[26] Wang Z, Huo Y, Fan Y, et al. Facile synthesis of carbon-rich g-C3N4 by copolymerization of urea and tetracyanoethylene for photocatalytic degradation of Orange II[J]. Journal of Photochemistry and Photobiology A: Chemistry, 2018, 358: 61-69.
[27] Li Y, Ho W, Lyu K, et al. Carbon vacancy-induced enhancement of the visible light-driven photocatalytic oxidation of NO over g-C3N4 nanosheets[J]. Applied Surface Science, 2018, 430: 380-389.
[28] 中国污水处理工程网.罗丹明B废水光催化处理技术[EB/OL](2015-6-28).http://www.dowater.com/jishu/2015-06-28/352561/.html.