Controllable synthesis of a 3D flower-like CeTiOx composite oxide exposing CeO2{100} plane and it supported Au catalyst for CO oxidation
-
摘要: 利用水热法制备了一种具有花朵状形貌的铈钛复合氧化物，该复合氧化物主要暴露CeO2{100}晶面。SEM、XRD表征结果表明，花朵状铈钛复合氧化物的形成主要分为两个阶段，即无定型的快速生长及缓慢结晶两个过程；在制备过程中，铈钛比例、KOH浓度、晶化时间和焙烧温度是该形貌形成的主要影响因素。其负载Au催化剂后常温即能实现CO的完全转化；TEM和H2-TPR结果表明，暴露的CeO2{100}晶面以及Au和载体的强相互作用是该催化剂具有高活性的主要原因。
-
关键词:
- CeO2{100}晶面 /
- 铈钛复合氧化物 /
- 水热法 /
- 金催化剂 /
- 一氧化碳氧化
Abstract: In this work, a flower-like CeTiOx composite oxide, predominantly exposing CeO2{100} plane, was synthesized by a simple hydrothermal method. The SEM and XRD results revealed the growth mechanism of CeTiOx composite oxide can be divided into two stages, including the rapid growth of amorphous and the following crystallization. The ratio of Ce/Ti, KOH concentration, crystallization time and calcination temperature are the key factors for the synthesis of the flower-like CeTiOx composite oxide. Au catalyst supported on this composite oxide exhibited superior activity for CO oxidation at room temperature. The TEM and H2-TPR results suggested that the exposed CeO2{100} plane and the strong interaction between Au and CeTiOx composite oxide are responsible for the high activity.-
Key words:
- CeO2{100} plane /
- CeTiOx composite oxide /
- hydrothermal method /
- gold catalyst /
- CO oxidation
-
图 1 不同铈钛比例条件下CeTiOx复合氧化物的SEM照片
(a): Ce0.2Ti0.8O2; (b): Ce0.45Ti0.55O2; (c): Ce0.6Ti0.4O2; (d): Ce0.8Ti0.2O2
Figure 1 SEM images of CeTiOx composite oxides with different Ce/Ti molar ratio
图 2 不同铈钛比例下CeTiOx复合氧化物的XRD谱图
a: TiO2; b: Ce0.2Ti0.8O2; c: Ce0.45Ti0.55O2; d: Ce0.6Ti0.4O2; e: Ce0.8Ti0.2O2; f: CeO2
Figure 2 XRD patterns of CeTiOx composite oxides with different Ce/Ti molar ratio
图 3 不同KOH浓度制得的Ce0.45Ti0.55O2复合氧化物的SEM照片和XRD谱图
(a): 3 mol/L; (b): 6 mol/L; (c): 9 mol/L; (d): 12 mol/L; (e): XRD
Figure 3 SEM images and XRD patterns of Ce0.45Ti0.55O2 composite oxides with different KOH concentrations
图 4 不同水热处理时间条件下Ce0.45Ti0.55O2复合氧化物的SEM照片
(a): 0; (b): 6 h; (c): 12 h; (d): 24 h; (e): 36 h; (f): 48 h
Figure 4 SEM images of Ce0.45Ti0.55O2 with different hydrothermal treatment time
图 5 不同焙烧温度条件下Ce0.45Ti0.55O2复合氧化物的SEM、TEM照片和XRD谱图
(a): 400 ℃; (b): 500 ℃; (c): 600 ℃; (d): 700 ℃; (e): 800 ℃; (f): XRD spectra
Figure 5 SEM and TEM images and XRD patterns of Ce0.45Ti0.55O2 at different calcination temperature
图 6 不同形貌Ce0.45Ti0.55O2及其负载Au催化剂的XRD谱图
a: Ce0.45Ti0.55O2-A; b: Au/Ce0.45Ti0.55O2-A; c: Ce0.45Ti0.55O2-F; d: Au/Ce0.45Ti0.55O2-F
Figure 6 XRD patterns of Ce0.45Ti0.55O2 with different morphologies and their supported Au catalysts
图 7 不同形貌Ce0.45Ti0.55O2及其负载Au催化剂的TEM和HR-TEM照片
(a1)、(a2)、(a3): Ce0.45Ti0.55O2-A; (b1)、(b2)、(b3): Au/Ce0.45Ti0.55O2-A; (c1)、(c2)、(c3): Ce0.45Ti0.55O2-F; (d1)、(d2)、(d3): Au/Ce0.45Ti0.55O2
Figure 7 TEM and HR-TEM images of Ce0.45Ti0.55O2 with different morphologies and their supported Au catalysts
图 8 不同形貌Ce0.45Ti0.55O2载体及其负载Au催化剂的H2-TPR谱图
a: Ce0.45Ti0.55O2-A; b: Au/Ce0.45Ti0.55O2-A; c: Ce0.45Ti0.55O2-F; d: Au/Ce0.45Ti0.55O2-F
Figure 8 H2-TPR spectra of Ce0.45Ti0.55O2 with different morphologies and their supported Au catalysts
图 9 不同形貌的Ce0.45Ti0.55O2载体及其负载Au催化剂的CO活性
a: Ce0.45Ti0.55O2-F; b: Ce0.45Ti0.55O2-A; c: Au/Ce0.45Ti0.55O2-A; d: Au/Ce0.45Ti0.55O2-F
Figure 9 CO catalytic performance test of Ce0.45Ti0.55O2 with different morphologies and their supported Au catalysts
表 1 不同形貌载体及其负载Au催化剂的氮吸附物理参数和Au负载量
Table 1 N2 adsorption properties and Au loadings of Ce0.45Ti0.55O2 with different morphologies and their supported Au catalysts
表 2 不同形貌载体及其负载Au催化剂的H2-TPR定量分析
Table 2 H2-TPR quantitative analysis of Ce0.45Ti0.55O2 with different morphologies and their supported Au catalysts
表 3 不同CeO2晶面的Au/CeO2催化剂CO催化性能对比
Table 3 Comparison of catalytic performance of Au/CeO2 catalysts with different CeO2 morphologies and crystal planes reported in recent years
-
[1] SUN Y A, SHEN Y N, JIA M L. Evolution of gold species in an Au/CeO2 catalyst and its impact on activity for CO oxidation[J]. Chem Res Chin Univ, 2010, 26 (3): 453-459. [2] HARUTA M, YAMADA N, KOBAYASHI T. Gold catalysts prepared by coprecipitation for low-temperature oxidation of hydrogen and of carbon monoxide[J]. J Catal, 1989, 115 (2): 301-309. doi: 10.1016/0021-9517(89)90034-1 [3] HARUTA M, TSUBOTA S, KOBAYASHI T. Low-temperature oxidation of CO over gold supported on TiO2, α-Fe2O3, and Co3O4[J]. J Catal, 1993, 144 (1): 175-192. doi: 10.1006/jcat.1993.1322 [4] PANDIAN L, LAURENT D, VINCENT R. Total oxidation of propene over Au/CeO2-Al2O3 catalysts: Influence of the CeO2 loading and the activation treatment[J]. Appl Catal B: Environ, 2010, 96 (1/2): 117-125. [5] MARIA P C, ALESSANDRO L, ANNA M V. Metal-support and preparation influence on the structural and electronic properties of gold catalysts[J]. Appl Catal A: Gen, 2006, 302 (2): 309-316. doi: 10.1016/j.apcata.2006.02.005 [6] LI Q, ZHANG Y H, CHEN G X. Ultra-low-gold loading Au/CeO2 catalysts for ambient temperature CO oxidation: Effect of preparation conditions on surface composition and activity[J]. J Catal, 2010, 273 (2): 167-176. doi: 10.1016/j.jcat.2010.05.008 [7] LI S H, ZHU H Q, QIN Z F. Morphologic effects of nano CeO2-TiO2 on the performance of Au/CeO2-TiO2 catalysts in low-temperature CO oxidation[J]. Appl Catal B: Environ, 2014, 144 : 498-506. doi: 10.1016/j.apcatb.2013.07.049 [8] QIAN K, HUANG W X, JIANG Z Q. Anchoring highly active gold nanoparticles on SiO2 by CoOx additive[J]. J Catal, 2007, 248 (1): 137-141. doi: 10.1016/j.jcat.2007.02.010 [9] WANG Z H, FU H F, TIAN Z W. Strong metal-support interaction in novel core-shell Au-CeO2 nanostructures induced by different pretreatment atmospheres and its influence on CO oxidation[J]. Nanoscale, 2016, 8 (11): 5865-5872. doi: 10.1039/C5NR06929G [10] ALESSANDRO L, LEONARDA F L, GABRIELLA D C. Structure and the metal support interaction of the Au/Mn oxide catalysts[J]. Chem Mater, 2010, 22 (13): 3952-3960. doi: 10.1021/cm100697b [11] LIU X J, LIU J F, CHANG Z. Crystal plane effect of Fe2O3 with various morphologies on CO catalytic oxidation[J]. Catal Commun, 2011, 12 (6): 530-534. doi: 10.1016/j.catcom.2010.11.016 [12] LIN S J, SUA G J, ZHENG M H. Synthesis of flower-like Co3O4-CeO2 composite oxide and its application to catalytic degradation of 1, 2, 4-trichlorobenzene[J]. Appl Catal B: Environ, 2012, 123/124 : 440-447. doi: 10.1016/j.apcatb.2012.05.011 [13] ZHENG Y H, CHENG Y, WANG Y S. Quasicubic alpha-Fe2O3 nanoparticles with excellent catalytic performance[J]. J Phys Chem B, 2006, 110 (7): 3093-3097. doi: 10.1021/jp056617q [14] XIE X W, LI Y, LIU Z Q. Low-temperature oxidation of CO catalysed by Co3O4 nanorods[J]. Nature, 2009, 458 (7239): 746-749. doi: 10.1038/nature07877 [15] LIU L J, JIANG Y Q, ZHAO H L. Engineering coexposed {001} and {101} facets in oxygen-deficient TiO2 nanocrystals for enhanced CO2 photoreduction under visible light[J]. ACS Catal, 2016, 6 (2): 1097-1108. [16] WANG G H, LI W C, JIA K M. Shape and size controlled alpha-Fe2O3 nanoparticles as supports for gold-catalysts: Synthesis and influence of support shape and size on catalytic performance[J]. Appl Catal A: Gen, 2009, 364 (1/2): 42-47. [17] ZIOLKOWSKI J, BARBAUX Y. Identification of sites active in oxidation of butene to butadiene and CO2 on CO3O4 in terms of the crystallochemical model of solid surface[J]. J Mol Catal, 1991, 67 (2): 199-215. doi: 10.1016/0304-5102(91)85047-6 [18] TTHX T S, FRANCESCO C, ZHANG X Q. Structure-activity map of ceria nanoparticles, nanocubes, and mesoporous architectures[J]. Chem Mater, 2016, 28 (20): 7287-7295. doi: 10.1021/acs.chemmater.6b02536 [19] HAUNG W X. Oxide nanocrystal model catalysts[J]. Acc Chem Res, 2016, 49 (3): 520-527. doi: 10.1021/acs.accounts.5b00537 [20] TA N, LIU J Y, SANTHOSH C. Stabilized gold nanoparticles on ceria nanorods by strong interfacial anchoring[J]. J Am Chem Soc, 2012, 134 (51): 20585-20588. doi: 10.1021/ja310341j [21] TIZIANO M, MICHELE M, MATTEO M. Fundamentals and catalytic applications of CeO2-based materials[J]. Chem Rev, 2016, 116 (10): 5987-6041. doi: 10.1021/acs.chemrev.5b00603 [22] HU Z, LIU X F, MENG D M. Effect of ceria crystal plane on the physicochemical and catalytic properties of Pd/ceria for CO and propane oxidation[J]. Acs Catal, 2016, 6 (4): 2265-2279. doi: 10.1021/acscatal.5b02617 [23] SUN C W, LI H, CHEN L Q. Study of flowerlike CeO2 microspheres used as catalyst supports for CO oxidation reaction[J]. J Phys Chem Solids, 2007, 68 (9): 1785-1790. doi: 10.1016/j.jpcs.2007.05.005 [24] LIU W, FENG L U, ZHANG C. A facile hydrothermal synthesis of 3D flowerlike CeO2 via a cerium oxalate precursor[J]. J Mater Chem A, 2013, 1 (23): 6942-6948. doi: 10.1039/c3ta10487g [25] ZHOU K B, WANG X, SUN X M. Enhanced catalytic activity of ceria nanorods from well-defined reactive crystal planes[J]. J Catal, 2005, 229 (1): 206-212. doi: 10.1016/j.jcat.2004.11.004 [26] MAI H X, SUN L D, ZHANG Y W. Shape-selective synthesis and oxygen storage behavior of ceria nanopolyhedra, nanorods, and nanocubes[J]. J Phys Chem B, 2005, 109 (51): 24380-24385. doi: 10.1021/jp055584b [27] SUN C W, SUN J, XIAO G L. Mesoscale organization of nearly monodisperse flowerlike ceria microspheres[J]. J Phys Chem B, 2007, 110 (27): 13445-13452. http://www.irgrid.ac.cn/handle/1471x/794192 [28] PUTLA S, BAITHY M, PADIGAPATI S R. Nano-Au/CeO2 catalysts for CO oxidation: Influence of dopants (Fe, La and Zr) on the physicochemical properties and catalytic activity[J]. Appl Catal B: Environ, 2014, 144 : 900-908. doi: 10.1016/j.apcatb.2013.08.035 [29] PENN R L. Kinetics of oriented aggregation[J]. J Phys Chem B, 2004, 108 (34): 12707-12712. doi: 10.1021/jp036490+ [30] CHEN Y, WANG Y S, ZHEGN Y H. Two-step self-assembly of nanodisks into plate-built cylinders through oriented aggregation[J]. J Phys Chem B, 2005, 109 (23): 11548-11551. doi: 10.1021/jp050641m [31] HUANG X S, SUN H, WANG L C. Morphology effects of nanoscale ceria on the activity of Au/CeO2 catalysts for low-temperature CO oxidation[J]. Appl Catal B: Environ, 2009, 90 (1/2): 224-232. http://www.sciencedirect.com/science/article/pii/S0926337309001039 [32] ZHONG L S, HU J S, CAO A M. 3D flowerlike ceria micro/nanocomposite structure and its application for water treatment and CO removal[J]. Chem Mater, 2007, 19 (7): 1648-1655. doi: 10.1021/cm062471b [33] QI J, CHEN J, LI G D. Facile synthesis of core-shell Au＠CeO2 nanocomposites with remarkably enhanced catalytic activity for CO oxidation[J]. Energy Environ Sci, 2012, 5 (10): 8937. doi: 10.1039/c2ee22600f -
下载:
点击查看大图
计量
- 文章访问数: 80
- HTML全文浏览量: 55
- PDF下载量: 11
- 被引次数: 0
