Preparation of H4SiW12O40/Bi2WO6 nano-photocatalyst by supercritical hydrothermal synthesis and its photocatalysis denitrification performance
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摘要: 采用超临界水热合成方式极速合成一种H4SiW12O40/Bi2WO6光催化剂,通过X射线衍射(XRD)、场发射扫描电子显微镜(SEM)、透射电子显微镜(TEM)、比表面积及孔隙度(BET)测定对所合成催化剂的结构和性质进行了考察,并以吡啶含量为15 mg/g的模拟油对光催化剂的脱氮效果进行评价。结果表明,该光催化剂为二维纳米片自组装成的三维球状结构,其中,H4SiW12O40与Bi2WO6不是简单的固载关系而是在超临界水热条件下生成一种新的晶相,正是由于这种晶相的存在,使得H4SiW12O40牢固固载在Bi2WO6光催化剂本体上的同时,对光生载流子进行了有效疏导,提升了H4SiW12O40/Bi2WO6光催化剂的使用寿命和光催化活性。本研究针对光催化剂制备周期与晶形发育的矛盾,将超临界水热技术与光催化剂模板导向合成技术有机结合,在获得良好晶形异质结构H4SiW12O40/Bi2WO6光催化剂的同时明显缩短了光催化剂的制备周期,从而降低了催化剂的制备成本,攻克了光催化剂工业化应用的主要矛盾,所制备的H4SiW12O40/Bi2WO6光催化剂轻质油脱氮效率达97%以上。Abstract: An immobilized nano-photocatalyst H4SiW12O40/Bi2WO6 was quickly prepared by the supercritical hydrothermal synthesis method. The properties, morphology and structure of the prepared catalysts were investigated and characterized by X-ray diffraction(XRD), scanning electron microscopy(SEM), and transmission electron microscope (TEM) and BET, respectively. The photocatalytic denitrification properties were evaluated by using the model oil with 15 mg/g pyridine. The results show that the photocatalyst is the self-assembly three-dimensional spherical structure by two-dimensional nano-flakes, and the relationship between Bi2WO6 and H4SiW12O40 is not a simple solid loading, but is a new crystal under the condition of supercritical water. It is because the existence of this kind of crystal that the H4SiW12O40 is firmly fixed on the Bi2WO6 photocatalyst and the photocatalytic activity and service life of H4SiW12O40/Bi2WO6 photocatalyst are improved. In view of the contradiction between the preparation period of photocatalyst and the crystal development, the supercritical hydrothermal technology and the photocatalyst template-oriented synthesis technology are organically combined to obtain the H4SiW12O40/Bi2WO6 photocatalyst with good crystal heterostructure and greatly shorten the preparation period of the photocatalyst, greatly reduce the preparation cost of the catalyst and overcome the main contradiction of the industrialized application of the photocatalyst. The nitrogen removal efficiency of the prepared H4SiW12O40/Bi2WO6 photocatalyst for light oil is as high as 97%.
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Key words:
- supercritical hydrothermal synthesis /
- H4SiW12O40 /
- Bi2WO6 /
- photocatalysis /
- denitrification
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表 1 传统水热法(a)和超临界水热法(b)制备的催化剂比表面积及平均孔径
Table 1 Specific surface area of the catalysts
Specific surface
area A/(m2·g-1)Average pore
size d/nma 24.87 4.89 b 30.15 3.92 表 2 不同方法制备周期对比
Table 2 Preparation period of the catalyst
Traditional
phase
synthesisMicrowave-
assisted liquid
phase synthesisSupercritical
hydrothermal
synthesis12h 6h 10s -
[1] FUJISHIMA A, HONDA K. Electrochemical photolysis of water at a semiconductor electrode[J]. Nature, 1972, 238(5358):37-38. doi: 10.1038/238037a0 [2] TANTIS I, BOUSIAKOU L, KARIKAS G A, LIANOS P. Photocatalytic and hotoelectrocatalytic degradation of the antibacterial agent ciprofloxacin[J]. Photochem Photobiol Sci, 2015, 14(3):603-607. doi: 10.1039/C4PP00377B [3] CARMONA R J, VELASCO L F, HIDALGO M C, NAVÍO J A, ANIA C O. Boosting the visible-light photoactivity of Bi2WO6 using acidic carbon additives[J]. Appl Catal A:Gen, 2015, 505:467-477. doi: 10.1016/j.apcata.2015.05.011 [4] TROVO A G, NOGUEIRA R F, AGUERA A, FERNANDEZ-ALBA A R, MALATO S. Degradation of the antibiotic amoxicillin by photo-Fenton process-chemical and toxicological assessment[J]. Water Res, 2011, 45(3):1394-1402. http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=73838d2c89f510f4f0a9134e7098ec3b [5] XUE J, MA S, ZHOU Y, ZHANG Z, HE M. Facile photochemical synthesis of Au/Pt/gC3N4 with plasmon-enhanced photocatalytic activity for antibiotic aegradation[J]. ACS Appl Mater Inter, 2015, 7(18):9630-9637. [6] LIU G, HAN K, YE H, ZHU C, GAO Y, LIU Y, ZHOU Y. Graphene oxide/triethanolamine modified titanate nanowires as photocatalytic membrane for water treatment[J]. Chem Eng J, 2017, 320:74-80. http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=ecff7b05d85a64a05d9f44e0af421850 [7] WANG X, NI Q, ZENG D, LIAO G, XIE C. Charge separation in branched TiO2 nanorod array homojunction aroused by quantum effect for enhanced photocatalytic decomposition of gaseous benzene[J]. Appl Surf Sci, 2016, 389:165-172. doi: 10.1016/j.apsusc.2016.07.090 [8] HOA P T, MANAGAKI S, NAKADA N, TAKADA H, SHIMIZU A, ANH D H, VIET P H, SUZUKI S. Antibiotic contamination and occurrence of antibiotic-resistant bacteria in aquatic environments of northern Vietnam[J]. Sci Total Environ, 2011, 409(15):2894-2901. http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=fb86a2186b883efa29a45c2dc9fc26bf [9] WANG J, TANG L, ZENG G, DENG Y, LIU Y, WANG L. Atomic scale g-C3N4/Bi2WO6 2D/2D heterojunction with enhanced photocatalytic degradation of ibuprofen under visible light irradiation[J]. Appl Catal B:Environ, 2017, 209:285-294. doi: 10.1016/j.apcatb.2017.03.019 [10] MENG X, ZHANG Z. Plasmonic Z-scheme Ag2O-Bi2MoO6 p-n heterojunction photocatalysts with greatly enhanced visible-light responsive activities[J]. Mater Lett, 2017, 189:267-270. doi: 10.1016/j.matlet.2016.11.114 [11] MENG X, ZHANG Z. Bi2MoO6 co-modified by reduced graphene oxide and palladium(Pd2+ and Pd0) with enhanced photocatalytic decomposition of phenol[J]. Appl Catal B:Environ, 2017, 209:383-393. doi: 10.1016/j.apcatb.2017.01.033 [12] ZHOU X, GAN L, ZHANG Q, XIONG X, LI H, ZHONG Z. High performance near-infrared photodetectors based on ultrathin SnS nanobelts grown via physical vapor deposition[J]. J Mater Chem C, 2016, 2111-2116. http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=98012db5d51372a3a557fd304b867b73 [13] MENG X, LI Z, ZENG H, CHEN J, ZHANG Z. MoS2 quantum dots-interspersed Bi2WO6 heterostructures for visible light-induced detoxification and disinfection[J]. Appl Catal B:Environ, 2017, 210:160-172. http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=551e897bbf52e3b94be23ca178507969 [14] CHEN D, NIU F, QIN L, WANG S, ZHANG N, HUANG Y. Defective BiFeO3 with surface oxygen vacancies:Facile synthesis and mechanism insight into photocatalytic performance[J]. Sol Energy Mater Sol Cells, 2017, 171:24-32. doi: 10.1016/j.solmat.2017.06.021 [15] WANG S, HAI X, DING X, CHANG K, XIANG Y, MENG X, YANG Z, CHEN H, YE J. Light-switchable oxygen vacancies in ultrafine Bi5O7Br nanotubes for boosting solar-driven nitrogen fixation in pure water[J]. Adv Mater, 2017, 29(31):1101774. http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=a64b07bce32716852c84f6e3284412f9 [16] MENG X, ZHANG Z. Ag/AgCl loaded Bi2WO6 composite:A plasmonic Z-scheme visible light-responsive photocatalyst[J]. Int J Photoenergy, 2016, 1-11. https://www.researchgate.net/publication/298796814_AgAgCl_Loaded_Bi_2_WO_6_Composite_A_Plasmonic_Z-Scheme_Visible_Light-Responsive_Photocatalyst [17] LIU X, LU Q, LIU J. Electrospinning preparation of one-dimensional ZnO/Bi2WO6, heterostructured sub-microbelts with excellent photocatalytic performance[J]. J Alloy Compd, 2016, 662:598-606. doi: 10.1016/j.jallcom.2015.12.050 [18] SONG C, WANG X, ZHANG J, CHEN X, LI C. Enhanced performance of direct zscheme CuS-WO3 system towards photocatalytic decomposition of organic pollutants under visible light[J]. Appl Surf Sci, 2017, 425:788-795. doi: 10.1016/j.apsusc.2017.07.082 [19] HUANG Y, KANG S, YANG Y, QIN H, NI Z, YANG S. Facile synthesis of Bi/Bi2WO6 nanocomposite with enhanced photocatalytic activity under visible light[J]. Appl Catal B:Environ, 2016, 196:89-99. doi: 10.1016/j.apcatb.2016.05.022 [20] MENG X, ZHANG Z. Synthesis and characterization of plasmonic and magnetically separable Ag/AgCl-Bi2WO6-Fe3O4-SiO2 core-shell composites for visible light-induced water detoxification[J]. J Colloid Interf Sci, 2017, 485:296-307. http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=861f04e19134fa57b0d98efba988ecae [21] 刘阳, 季宏伟, 周德凤, 朱晓飞, 李朝晖. TiO2/LaFeO3微纳米纤维的可控制备及光催化性能[J].高等学校化学学报, 2014, 35(1):19-25. http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=gdxxhxxb201401003LIU Yang, JI Hong-wei, ZHOU De-feng, ZHU Xiao-fei, LI Zhao-hui.Controllable synthesis and photocatalytic activity of TiO2/LaFeO3 micro-nanofibers[J]. Chem J Chin Univ, 2014, 35(1):19-25. http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=gdxxhxxb201401003 [22] LITKE A, HENSEN E J M, HOFMANN J P. Role of dissociatively adsorbed water on the formation of shallow trapped electrons in TiO2 photocatalysts[J]. J Chem Phys, 2017, 121:10153-10162. http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=d3147bc2b815caf434ea7897f13b04e2 [23] JARAMILLO-PÁEZ C, NAVÍO J A, HIDALGO M C, BOUZIANI A, AZZOUZI M E. Mixed α-Fe2O3/Bi2WO6 oxides for photoassisted hetero-fenton degradation of methyl orange and phenol[J]. J Photochem Photobiol A, 2017, 332:521-533. doi: 10.1016/j.jphotochem.2016.09.031 [24] MENG X, ZHANG Z. Pd-doped Bi2MoO6 plasmonic photocatalysts with enhanced visible light photocatalytic performance[J]. Appl Surf Sci, 2017, 392:169-180. doi: 10.1016/j.apsusc.2016.08.113 [25] SH/T 0162-1992, Method for the determination of basic nitrogen in petroleum products[S]. Sinopec Group, 1992. [26] 陈颖, 邢宸, 姬生伦, 梁宏宝.微波液相法一步合成H3PW12O40/Bi2WO6光催化剂及其脱氮性能[J].高等学校化学学报, 2014, 35(6):1277-1285. http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=gdxxhxxb201406024CHEN Ying, XING Chen, JI Shen-lun, LIANG Hong-bao. One-step preparation of H3PW12O40/Bi2WO6 nano-photocatalysts by microwave liquid process and its photocatalysis denitrification properties[J]. Chem J Chin Univ, 2014, 35(6):1277-1285. http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=gdxxhxxb201406024 [27] ZHOU L, WANG W Z, ZHANG L S. Ultrasonic-assisted synthesis of visible-light-indyced Bi2MO6(M=W, Mo)[J]. J Mol Catal A:Chem, 2007, 268:195-200. doi: 10.1016/j.molcata.2006.12.026 [28] TANG J W, ZOU Z G, YE J H. Photophysical and photocatalytic properties of AgInW2O8[J]. Phys Inorg Chem, 2004, 35(10). doi: 10.1021-jp0359891/ [29] OZER R R, FERRY J L. Investigation of the photocatalytic activity of TiO2-polyoxometalate systems[J]. Environ Sci Technol, 2001, 35(15):3242-3246. doi: 10.1021/es0106568