Preparation and photocatalytic properties CuS-Bi2WO6/carbon nanofibers composites
-
摘要: 铬是一种常见的重金属污染物,广泛用于各种工业过程。采用溶剂热法制备了不同CNFs(活性纳米碳纤维)含量的CuS-Bi2WO6/CNFs复合光催化剂,改善可见光照射下六价铬的还原。通过XRD、SEM、TEM、FTIR、XPS、UV-Vis、PL和光电流等技术对样品的晶型、形貌、结构、元素组成、表面官能团、光学性质等进行了测试与表征,并考察了CuS-Bi2WO6/CNFs光催化还原Cr(VI)的活性。结果表明,CuS-Bi2WO6/CNFs复合材料的光催化活性明显高于CuS、Bi2WO6和CuS-Bi2WO6。在可见光照射下,1%CuS-Bi2WO6/CNFs对Cr(VI)还原表现出优异的光催化活性,在3 h内还原率为98%。1%CuS-Bi2WO6/CNFs复合材料在4次循环后也表现出良好的稳定性和可回收性。此外,活性基团捕获实验表明,羟基自由基(•OH)、光生空穴(h+)和超氧自由基(•O2−)参与了CuS-Bi2WO6/CNFs对Cr(VI)的还原,而•O2−是该体系的主要活性组分,并在此基础上初步探讨了光催化反应机制。本文的研究结果表明,通过简单可控的溶剂热法,可以实现CuS-Bi2WO6/CNFs的制备,并且证实了CuS-Bi2WO6/CNFs复合材料在六价铬处理方面的良好前景。Abstract: Chromium is a common heavy metal pollutant and extensively used in variety of industrial processes. CuS-Bi2WO6/CNFs (carbon nanofibers) composite photocatalysts with different CNFs content were prepared by solvothermal method to remove Cr(VI) from the aqueous solution. The crystal form, morphology, structure, elemental composition, surface functional groups and optical properties of the samples were characterized by XRD, SEM, TEM, FTIR, XPS, UV-Vis and PL. The photocatalytic degradation of Cr(VI) by CuS-Bi2WO6/CNFs composite materials was evaluated. The results show that the photocatalytic activity of the CuS-Bi2WO6/CNFs composite is obviously higher than that of the CuS、Bi2WO6 and CuS/Bi2WO6. Under visible light irradiation, 1%CuS-Bi2WO6/CNFs composites show higher photocatalytic degradation performance, and the reduction rate of Cr(VI) is 98% within 3 h. And 1%CuS-Bi2WO6/CNFs composites also show strong stability and recoverability after four cycles. In addition, the experimental results of active group capture show that hydroxyl radical (•OH), photogenerated hole (h+) and superoxide radical (•O2−) are involved in the reduction of Cr(VI) on CuS-Bi2WO6/CNFs, and •O2− is the main active components of the system. The photocatalytic reaction mechanism was discussed. The research results show that the preparation of CuS-Bi2WO6/CNFs can be achieved by a simple and controllable solvothermal method, and it has confirmed the good prospects of CuS-Bi2WO6/CNFs composites in the treatment of hexavalent chromium.
-
Key words:
- photocatalytic /
- composite photocatalyst /
- Cr(VI) /
- reduction /
- carbon nanofibers /
- CuS /
- Bi2WO6
-
图 3 Bi2WO6 (a)、5%CuS-Bi2WO6 (b)、1%CuS-Bi2WO6/CNFs (c) 光催化剂的SEM图像,5%CuS-Bi2WO6 (d)、1%CuS-Bi2WO6/CNFs(20 nm) (e)和1%CuS-Bi2WO6/CNFs(10 nm) (f) 的TEM图像
Figure 3. SEM images of Bi2WO6 (a), 5%CuS-Bi2WO6 (b), 1%CuS-Bi2WO6/CNFs (c) and TEM images of 5%CuS-Bi2WO6 (d), 1%CuS-Bi2WO6/CNFs (20 nm) (e) and 1%CuS-Bi2WO6/CNFs (10 nm) (f)
表 1 CuS-Bi2WO6/CNFs复合材料的命名
Table 1. Naming of CuS-Bi2WO6/CNFs composite
Specimen Mass ratio of CNFs∶
CuS-Bi2WO6/%0.5%CuS-Bi2WO6/CNFs 0.5 1%CuS-Bi2WO6/CNFs 1 2%CuS-Bi2WO6/CNFs 2 4%CuS-Bi2WO6/CNFs 4 6%CuS-Bi2WO6/CNFs 6 -
[1] XIONG J, DU J, ZENG S, et al. CuS nanosheet decorated Bi5O7I composite for the en-hanced photocatalytic reduction activity of aqueous Cr(VI)[J]. Journal of Inorganic Materials,2020,36(3):356. [2] SUNG Y H, BIRO R P, PRIOR Y, et al. Synthesis of SnS2/SnS fullerene-like nanoparticles: Superlattice with polyhedral shape[J]. American Chemical Society,2003,125(34):10470-10474. doi: 10.1021/ja036057d [3] CHIA H, WANG S L, YU M T. Photocatalytic reduction of Cr(VI) in the presence of NO3− and CI− electrolytes as influenced by Fe(III)[J]. Environmental Science & Technology,2007,22(41):7907-7914. [4] HE Z, CAI Q, WU M, et al. Photocatalytic reduction of Cr(VI) in an aqueous suspension of surface-fluorinated anatase TiO2 nanosheets with exposed facets[J]. Industrial & Engineering Chemistry Research,2013,52(28):9556-9565. [5] YI H, ZENG G, LAI C, et al. Environment-friendly fullerene separation methods[J]. Chemical Engineering Journal,2017,330:134-145. doi: 10.1016/j.cej.2017.07.143 [6] 刘自力, 韦江慧. 光催化降解糖蜜酒精废水的研究[J]. 工业催化, 2004, 12(2):31-34. doi: 10.3969/j.issn.1008-1143.2004.02.008LIU Zili, WEI Jianghui. Photocatalytic degradation of wastewater from fermented molasses[J]. Industrial Catalysis,2004,12(2):31-34(in Chinese). doi: 10.3969/j.issn.1008-1143.2004.02.008 [7] 刘旺平, 王鑫, 张帅, 等. Ag和介孔碳改性Bi2WO6光催化剂的合成及其可见光下的光催化性能[J]. 复合材料学报, 2015, 32(4):1187-1193.LIU Wangping, WANG Wenzhong, ZHANG Shuai, et al. Synthesis of Ag and mesoporous carbon modified Bi2WO6 photocatalyst and its photocatalytic property in visible light[J]. Acta Materiae Compositae Sinica,2015,32(4):1187-1193(in Chinese). [8] 张志洁, 王文中. 高活性可见光响应钨酸铋光催化剂的制备[C]. 第十三届全国太阳能光化学与光催化学术会议学术论文集. 北京, 2012.ZHANG Zhihao, WANG Wenzhong. Preparation of highly active visible light response bismuth tungstate photocatalyst[C]. Academic Proceedings of the 13th National Conference on Solar Photochemistry and Photocatalysis. Beijing, 2012(in Chinese). [9] TANG J, ZOU Z, YE J. Photophysical and photocatalytic properties of Bi2WO6[J]. Catalysis Letters,2004,95(53):250-270. [10] 李小芳. 新型钨酸铋可见光催化剂的制备改性及降解低浓度甲苯性能研究[D]. 杭州: 浙江大学, 2012.LI Xiaofang. Study on the preparation and modification of a new type of bismuth tungstate visible light catalyst and its performance in degradation of low-concentration toluene[D]. Hangzhou: Zhejiang University, 2012(in Chinese). [11] CAI Z, ZHOU Y, MA S, et al. Enhanced visible light photocatalytic performance of g-C3N4/CuS p-n heterojunctions for degradation of organic dyes[J]. Journal of Photochemistry and Photobiology A: Chemistry,2017,348:168-178. doi: 10.1016/j.jphotochem.2017.08.031 [12] GAO L, DU J, MA T. Cysteine-assisted synthesis of CuS-TiO2 composites with enhanced photocatalytic activity[J]. Ceramics International,2017,43(12):9559-9563. doi: 10.1016/j.ceramint.2017.04.093 [13] BHOI Y P, BEHREA C, MAJHI D, et al. Visible light-assisted photocatalytic mineralization of diuron pesticide using novel type II CuS/Bi2W2O9 heterojunctions with a hierarchical microspherical structure[J]. New Journal of Chemistry,2018,42(1):281-292. doi: 10.1039/C7NJ03390G [14] BHOI Y P, MISHRA B G. Photocatalytic degradation of alachlor using type-II CuS/BiFeO3 heterojunctions as novel photocatalyst under visible light irradiation[J]. Chemical Engineering Journal,2018,344:391-401. doi: 10.1016/j.cej.2018.03.094 [15] KAMANIFAR M, ALLAHRESANI A, NAGHIZDEH A. Synthesis and characterizations of a novel CoFe2O4@CuS magnetic nanocomposite and investigation of its efficiency for photocatalytic degradation of penicillin gantibiotic in simulated wastewater[J]. Journal of Hazardous Materials,2019,366:545-555. doi: 10.1016/j.jhazmat.2018.12.046 [16] GUO L, ZHANG K, HAN X, et al. 2D in-plane CuS/Bi2WO6 p-n heterostructures with promoted visible-light-driven photo-fenton degradation performance[J]. Nanomaterials (Basel),2019,9(8):1-18. [17] MAO W, ZHANG L, WANG T, et al. Fabrication of highly efficient Bi2WO6/CuS composite for visible-light photocatalytic removal of organic pollutants and Cr(VI) from wastewater[J]. Frontiers of Environmental Science & Engineering,2020,15(4):52-65. [18] WANG Y, SUNARSO J, WANG F, et al. Electrospinning and hydrothermal synthesis of recyclable MoS2/CNFs hybrid with enhanced visible-light photocatalytic performance[J]. Ceramics International,2017,43(14):11028-11033. doi: 10.1016/j.ceramint.2017.05.145 [19] GU H, HUANG Y, ZUO L, et al. Graphene sheets wrapped carbon nanofibers as a highly conductive three-dimensional framework for perpendicularly anchoring of MoS2: Advanced electrocatalysts for hydrogen evolution reaction[J]. Electrochimica Acta,2016,219:604-613. doi: 10.1016/j.electacta.2016.10.015 [20] ZHANG Y, SHAO C, LI X, et al. Controllable synthesis and enhanced visible photocatalytic degradation performances of Bi2WO6-carbon nanofibers heteroarchitectures[J]. Journal of Sol-Gel Science and Technology,2014,70(1):149-158. doi: 10.1007/s10971-014-3284-x [21] ZHOU H, WEN Z, LIU J, et al. Z-scheme plasmonic Ag decorated WO3/Bi2WO6 hybrids for enhanced photocatalytic abatement of chlorinated-VOCs under solar light irradiation[J]. Applied Catalysis B: Environmental,2019,242:76-84. doi: 10.1016/j.apcatb.2018.09.090 [22] DOUGLAS B. MAWHINNEY V N, ANYA K, et al. Infrared spectral evidence for the etching of carbon nanotubes-ozone oxidation at 298 K[J]. American Chemical Society,2000,122:2383-2384. doi: 10.1021/ja994094s [23] TJMEN G, GEUS J W, DIEDERIK C K. Surface structure of untreated parallel and fishbone carbon nanofibres-An infrared study[J]. ChemPhysChem,2002,2:209-214. [24] QIN Y H, YANG H H, ZHANG X S, et al. Electrophoretic deposition of network-like carbon nanofibers as a palladium catalyst support for ethanol oxidation in alkaline media[J]. Carbon,2010,48(12):3323-3329. doi: 10.1016/j.carbon.2010.05.010 [25] ALI A, BAHETI V, MILITKY J. Energy harvesting performance of silver electroplated fabrics[J]. Materials Chemistry and Physics,2019,231:33-40. doi: 10.1016/j.matchemphys.2019.02.063 [26] YANG J, WANG X, CHEN Y, et al. Enhanced photocatalytic activities of visible-light driven green synthesis in water and environmental remediation on Au/Bi2WO6 hybrid nanostructures[J]. RSC Advances,2015,5(13):9771-9782. doi: 10.1039/C4RA15349A [27] DAS K, MAJHI D, BHOOI Y P, et al. Combustion synthesis, characterization and photocatalytic application of CuS/Bi4Ti3O12 p–n heterojunction materials towards efficient degradation of 2-methyl-4-chlorophenoxyacetic acid herbicide under visible light[J]. Chemical Engineering Journal,2019,362:588-599. doi: 10.1016/j.cej.2019.01.060 [28] CHEN P, CHEN L, ZENG Y, et al. Three-dimension hierarchical heterostructure of CdWO4 microrods decorated with Bi2WO6 nanoplates for high-selectivity photocatalytic benzene hydroxylation to phenol[J]. Applied Catalysis B: Environmental,2018,234:311-317. doi: 10.1016/j.apcatb.2018.04.028 [29] CHEN S, LI X, ZHOU W, et al. Carbon-coated Cu-TiO2 nanocomposite with enhanced photostability and photocatalytic activity[J]. Applied Surface Science,2019,466:254-261. doi: 10.1016/j.apsusc.2018.10.036 [30] MAO W, WANG T, WANG H, et al. Novel Bi2WO6 loaded g-C3N4 composites with enhanced photocatalytic degradation of dye and pharmaceutical wastewater under visible light irradiation[J]. Journal of Materials Science: Materials in Electronics,2018,29(17):15174-15182. doi: 10.1007/s10854-018-9659-y [31] 罗伟, 冯小青, 黄影, 等. 微波水热合成花球状BiOCl光催化降解甲硝唑[J]. 中国环境科学, 2020, 40(4):1545-1554. doi: 10.3969/j.issn.1000-6923.2020.04.020LUO Wei, FENG Xiaoqing, HUANG Ying, et al. Photocatalytic degradation of metronidazole using flower-like BiOCl prepared by microwave hydrothermal method[J]. China Environmental Science,2020,40(4):1545-1554(in Chinese). doi: 10.3969/j.issn.1000-6923.2020.04.020 [32] WANG Y J, BAO S Y, LIU Y Q, et al. Efficient photocatalytic reduction of Cr(VI) in aqueous solution over CoS2/g-C3N4–rGO nanocomposites under visible light[J]. Applied Surface Science,2020,510:145495-145505. doi: 10.1016/j.apsusc.2020.145495 [33] WANG X L, PEHKONEN S O, RAY A K. Removal of Aqueous Cr(VI) by a combination of photocatalytic reduction and coprecipitation[J]. Industrial and Engineering Chemistry Research,2004,43(7):1665-1672. doi: 10.1021/ie030580j [34] CHEN F, YANG Q, WANG Y L, et al. Efficient construction of bismuth vanadate-based Z-scheme photocatalyst for simultaneous Cr(VI) reduction and ciprofloxacin oxidation under visible light: Kinetics, degradation pathways and mechanism[J]. Chemical Engineering Journal,2018,348:157-170. doi: 10.1016/j.cej.2018.04.170 [35] YANG J J, CHEN D M, ZHANG Y M, et al. 3D–3D porous Bi2WO6/graphene hydrogel composite with excellent synergistic effect of adsorption-enrichment and photocatalytic degradation[J]. Applied Catalysis B: Environmental,2017,205:228-237. doi: 10.1016/j.apcatb.2016.12.035