Preparation of BiOI/BiOBr hetero-structured photocatalyst by grinding-calcination route and its photocatalytic performance
-
摘要: 首先通过沉淀法制备BiOBr和BiOI纳米粉体，然后在主体BiOBr光催化剂中掺杂不同含量的共催化剂BiOI，充分研磨后在不同温度下进行煅烧3 h，制备了BiOI/BiOBr系列复合物，其中BiOI的质量分数分别为1%，2%，4%和8%.采用氮气物理吸附、X射线粉末衍射(XRD)、扫描电镜(SEM)、傅里叶变换红外光谱(FT-IR)、紫外-可见(UV-Vis) 漫反射(DRS) 和光电流测试等技术对所制备的样品进行表征.以酸性橙Ⅱ为模拟污染物, 在可见光下考察了煅烧温度和BiOI复合含量对BiOBr主体光催化剂的光催化性能的影响.研究表明，当复合BiOI的含量为4%，煅烧温度为400 ℃时所制备的复合光催化剂表现出最高光催化性能，其降解效率分别是纯BiOBr和BiOI的1.7和1.9倍.复合BiOI促进了催化剂对可见光的吸收，同时经过研磨和煅烧形成的BiOI/BiOBr异质相结，促进了光生电子(e-) 和空穴(h+) 的分离，提高了光催化活性.
-
关键词:
- 研磨 /
- 煅烧 /
- BiOI/BiOBr复合物 /
- 光催化 /
- 活性提高
Abstract: Pure BiOBr and BiOI nanopowders were first synthesized by precipitation method. BiOBr main photocatalyst and BiOI cocatalyst with different contents were mixed and grinded. After grinding, the composite powder was calcined at different temperatures. The produced BiOI/BiOBr hetero-structured photocatalysts (BiOI mass fraction content: 1%, 2%, 4%, 8%) were characterized by N2-physical adsorption, X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier translation infrared spectroscopy (FT-IR), and UV-Vis diffuse reflectance spectroscopy (DRS) and photoelectrochemical measurements. Acid orange Ⅱ dye was selected as degradation target pollutant under visible light irradiation. The effects of BiOI coupling concentration and calcination temperature on the photocatalytic performance were investigated. The results show that the BiOI/BiOBr composite photocatalyst with 4% mass fraction of BiOI and calcination at 400 ℃ show about 0.7 and 0.9 times of increasement in degradation rate compared to pure BiOBr and BiOI, respectively. Coupling of BiOI cocatalyst promoted the visible light absorption. Moreover, the formation of BiOI/BiOBr hetero-structure could restrain the recombination rate of photogenerated electrons (e-) and holes (h+). These two reasons could mainly account for the boosting of photocatalytic activity.-
Keywords:
- grinding /
- calcination /
- BiOI/BiOBr composite /
- photocatalysis /
- activity increase
-
配置好的环烷酸，皂化后并不是简单的真溶液，而是水分散在油相中的微乳状液体系，萃取稀土时，上述液体系会使微乳状液破乳。通过串级萃取理论计算得出的有机相理论流量不夹带水份，实际生产中皂化好的环烷酸往往又夹带水份，因此，为达到正常的萃取分离效果，保证产品质量，需要对有坑相理论流量进行校正，即先估算一个百分数，但不可避免地使理论值与实际值有时出现偏差。
一 公式推导
今设：
Vs实 进槽有机相实际流量 1/min
Vs理 计算的有机相理论流量
ε 有机相皂化度
C 皂化有机相氨水浓度(N)
V1 未皂化的有机相体积(1)
V2 将V1皂化为皂化度ε的氨水体积
则：
(1) 
(2) 将式(2)代入式(1)得
(3) 令
(4) 
(5) 二 讨 论
1.系数k与有机相皂化度成正比，皂化度越大K值越大，反之亦然。K和皂化有机相的氨水浓度成反比。
2.公式(4)和(5)，适周于氨水皂化有机相时，水均匀分布于有机相中的任何体系。它的导出，为确定▽s实提供理论依据，为准确地计算整个槽体平衡提供可靠依据。
-
![]()
图 2 合成4% BiOI/BiOBr在不同温度煅烧下的SEM像
Fig 2. SEM images of 4% BiOI/BiOBr samples calcined at different temperatures
![]()
图 3 样品4% BiOI/BiOBr在不同煅烧温度下煅烧后的FT-IR谱
Fig 3. FT-IR spectra of 4% BiOI/BiOBr samples calcined at different temperatures
![]()
图 5 样品BiOBr、BiOI和4% BiOI/BiOBr的光电流曲线
Fig 5. Transient photocurrent density responses of BiOBr, BiOI and 4% BiOI/BiOBr samples
![]()
图 6 在400 ℃煅烧下制备的BiOBr, BiOI和4% BiOI/BiOBr和未煅烧的4% BiOI/BiOBr样品活性比较
Fig 6. Comparison of photocatalytic activity of BiOBr, BiOI and 4% BiOI/BiOBr without calcination and calcination at 400 ℃
![]()
图 7 不同温度煅烧后的4% BiOI/BiOBr样品活性比较
Fig 7. Comparison of photocatalytic activity of 4% BiOI/BiOBr calcined at different temperature
![]()
图 8 添加2 mmol的叔丁醇和对苯醌对4% BiOI/BiOBr样品光催化活性的影响
Fig 8. Effects of addition of 2 mmol p-benzoquinone and tert-butyl alcohol on photocatalytic activity of 4% BiOI/BiOBr
![]()
图 9 BiOBr/BiOI复合光催化剂的光催化机理
Fig 9. Proposed photocatalytic mechanism of BiOBr/BiOI composite
表 1 样品的比表面积
Table 1 Specific surface area of samples
样品 比表面积/(m2·g) 样品 比表面积/(m2·g-1) BiOBr (400 ℃) 4.18 8% BiOI/BiOBr (400 ℃) 7.75 BiOI (400 ℃) 5.03 4% BiOI/BiOBr (300 ℃) 13.53 1% BiOI/BiOBr (400 ℃) 6.82 4% BiOI/BiOBr (350 ℃) 11.76 2% BiOI/BiOBr (400 ℃) 7.83 4% BiOI/BiOBr (450 ℃) 6.76 4% BiOI/BiOBr (400 ℃) 8.27 4% BiOI/BiOBr (500 ℃) 3.06 
下载: 导出CSV
表 2 所制备样品的带隙能与吸收边
Table 2 Band gap energy and absorption edge of samples
样品 带隙能/eV 吸收边/nm BiOBr (400 ℃) 2.88 430 BiOI (400 ℃) 2.03 610 1% BiOI/BiOBr (400 ℃) 2.82 440 2% BiOI/BiOBr (400 ℃) 2.83 438 4% BiOI/BiOBr (400 ℃) 2.77 448 8% BiOI/BiOBr (400 ℃) 2075 450 4% BiOI/BiOBr (300 ℃) 2053 490 4% BiOI/BiOBr (350 ℃) 2076 449 4% BiOI/BiOBr (450 ℃) 2076 450 4% BiOI/BiOBr (500 ℃) 2076 450
下载: 导出CSV
-
[1] 薛霜霜, 何洪波, 余长林.稀土上转换用于提高半导体化合物光催化效率的研究进展[J].有色金属科学与工程, 2015, 6(4): 97-103. http://ysjskx.paperopen.com/oa/DArticle.aspx?type=view&id=201504020 [2] 何洪波, 薛霜霜, 余长林.钨基半导体光催化剂研究进展[J].有色金属科学与工程, 2015, 6(5): 32-39. http://ysjskx.paperopen.com/oa/DArticle.aspx?type=view&id=201505007 [3] 陈建钗, 薛霜霜, 余长林.稀土在非TiO2光催化剂的改性研究[J].有色金属科学与工程, 2015, 6(1): 99-105. http://ysjskx.paperopen.com/oa/DArticle.aspx?type=view&id=201501019 [4] 魏龙福, 余长林, 陈建钗, 等.水热法合成Ag2CO3/ZnO异质结复合光催化剂及其光催化性能[J].有色金属科学与工程, 2014, 5(1): 47-53. http://ysjskx.paperopen.com/oa/DArticle.aspx?type=view&id=201401009 [5] 魏龙福, 余长林.石墨烯/半导体复合光催化剂的研究进展[J].有色金属科学与工程, 2013, 4(3): 34-39. http://ysjskx.paperopen.com/oa/DArticle.aspx?type=view&id=201303007 [6] YU C L, YU J C, CHAN M. Sonochemical fabrication of fluorinated mesoporous titanium dioxide microspheres[J]. Journal of Solid State Chemistry, 2009, 182(5): 1061-1069. doi: 10.1016/j.jssc.2009.01.033
[7] 余长林, 杨凯.异质结构的复合光催化材料的研究新进展[J].有色金属科学与工程, 2010, 2(1): 16-21. http://www.cnki.com.cn/Article/CJFDTOTAL-JXYS201006004.htm [8] 操芳芳, 余长林, 杨凯, 等.声化学制备纳米光催化材料研究进展[J].有色金属科学与工程, 2011, 2(5): 12-17. http://ysjskx.paperopen.com/oa/DArticle.aspx?type=view&id=201105003 [9] YU C L, ZHOU W Q, FAN Q Z, et al. Ultrasonic fabrication of n-doped TiO2 nanocrystals with mesoporous structure and enhanced visible light photocatalytic activity[J]. Chinese Journal of Catalysis, 2013, 34: 1250-255. doi: 10.1016/S1872-2067(12)60578-6
[10] AHERN J C, FAIRCHILD R, THOMAS J S, et al. Characterization of BiOX compounds as photocatalysts for the degradation of pharmaceuticals in water[J]. Applied Catalysis B: Environmental, 2015, 179: 229-238. doi: 10.1016/j.apcatb.2015.04.025
[11] 姬磊, 王浩人, 于瑞敏, 等.异质型BiOI/NaBiO3光催化剂的合成及其光催化性能[J].无机化学学报, 2015, 31(3): 521-528. http://www.cqvip.com/QK/93659X/201503/664227174.html [12] XIA J X, DI J, LI H T, et al. Ionic Liquid-induced strategy for carbon quantum dots/biOX (X=Br, Cl) hybrid nanosheets with superior visible light-driven photocatalysis[J]. Applied Catalysis B: Environmental, 2016, 181: 260-269. doi: 10.1016/j.apcatb.2015.07.035
[13] YU C L, CAO F F, LI G, et al. Novel noble metal (Rh, Pd, Pt)/BiOX (Cl, Br, I) composite photocatalysts with enhanced photocatalytic performance in dye degradation[J]. Separation and Purification Technology, 2013, 120: 110-122. doi: 10.1016/j.seppur.2013.09.036
[14] JIA M K, HU X L, WANG S L, et al. Photocatalytic properties of hierarchical BiOXs obtained via an ethanol-assisted solvothermal process[J]. Journal of Environmental Sciences, 2015, 35: 172-180. doi: 10.1016/j.jes.2014.09.045
[15] YU C L, LI G, KUMAR S, et al. Phase transformation synthesis of novel Ag2O/Ag2CO3 heterostructures with high visible light efficiency in photocatalytic degradation of pollutants[J]. Advanced Materials, 2014, 26: 892-898. doi: 10.1002/adma.v26.6
[16] XIAO X, HAO R, LING M, et al. One-pot solvothermal synthesis of three-dimensional (3D) BiOI/BiOCl composites with enhanced visible-light photocatalytic activites for the degradation of bisphenol-A[J]. Journal of Hazardous Materials, 2012, 233: 122-130. http://www.sigmaaldrich.com/catalog/papers/22818177
[17] YU C L, LI G, KUMAR S, et al. Stable Au25(SR)18/TiO2 Composite nanostructure with enhanced visible light photocatalytic activity[J]. Journal of Physical Chemistry Letters, 2013(4): 2847-2852. https://www.researchgate.net/profile/Gao_Li3/publication/255961139_Stable_Au25SR18TiO2_Composite_Nanostructure_with_Enhanced_Visible_Light_Photocatalytic_Activity/links/00b4952150539ccd4b000000/Stable-Au25SR18-TiO2-Composite-Nanostructure-with-Enhanced-Visible-Light-Photocatalytic-Activity.pdf
[18] KONG D S, WEI Y J, LI X X, et al. pH Dependent behavior and effects of photoinduced surface states during water photooxidation at TiO2/solution interface: studied by capacitance measurements[J]. Journal of The Electrochemical Society, 2014, 161(3): H144-H153. doi: 10.1149/2.083403jes
[19] YU C L, YU J C, CHAN M. Sonochemical fabrication of fluorinated mesoporous titanium dioxide microspheres[J]. Journal of Solid State Chemistry, 2009, 182: 1061-1069. doi: 10.1016/j.jssc.2009.01.033
[20] XIAO X, HAO R, LIANG M, et al. One-pot solvothermal synthesis of three-dimensional (3D) BiOI/BiOCl composites with enhanced visible-light photocatalytic activites for the degradation of bisphenol-A[J]. Journal of Hazardous Materials, 2012, 233/ 234: 122-130. doi: 10.1016/j.jhazmat.2012.06.062
计量
- 文章访问数: 113
- HTML全文浏览量: 53
- PDF下载量: 6
