水相重构法制备Ce改性Mg-Al复合氧化物及其在丙酮气相缩合反应中的应用

doi:10.7503/cjcu20150653

摘要/Abstract

摘要：

通过水相重构法合成了Ce改性的Mg-Al复合金属氧化物HTc-Ce, 采用X射线粉末衍射(XRD)、 X射线光电子能谱(XPS)、透射电子显微镜(TEM)和氮气吸附-脱附表征了复合金属氧化物的组成和表面结构. 水相重构过程使复合金属氧化物产生更多缺陷位, 从而具有更多碱性位. Ce通过液相重构过程有效进入到水滑石的骨架, 撑大了水滑石的层间距, 进一步增加了催化剂的可接触碱性位, 同时氧化铈丰富的氧空位显著提高了表面碱性位, 特别是强碱性位的数量. XPS实验结果表明, 三价Ce在氧化铈中的含量约为30%, 氧空位提高有助于改善表面氧的迁移. 原位红外漫反射(in situ DRIFTS)证实增加了表面低配氧的数量, CO₂-程序升温脱附(CO₂-TPD)实验证实了Ce的引入提高了表面强碱性位浓度. 水相重构法合成Ce修饰的Mg-Al复合金属氧化物对于丙酮自缩合反应具有高效活性, HTc-Ce-3.2催化的丙酮转化率达到56.8%, 是HTc催化剂的2.5倍, 该催化剂因其层间距增加和结构疏松更有利于五聚产物的生成.

关键词: 水相重构, 氧空位, 复合金属氧化物, 丙酮气相自缩合, 铈改性

Abstract:

Ce modified Mg-Al mixed metal oxides(HTc-Ce) were prepared by aqueous reconstruction method. The construct and surface properties of catalysts were characterized by X-ray diffraction(XRD), X-ray photoelectron spectrometry(XPS), transmission electron microscopy(TEM) and N₂ adsorption and desorption isotherms. Aqueous reconstruction process promotes forming more defects on the Mg-Al mixed oxides, Ce is successfully embedded into the interlayer of hydrotalcite framework and enlarges its spaces, which improves the accessibility of active sites. The oxygen mobility of ceria increases the amount of basic sites on the surface. XPS results indicate that there is about 30% of Ce(Ⅲ) in cerium oxides. Oxygen vacancies are beneficial to enhancing the ability of oxygen mobility. In situ diffuse reflectance infrared Fourier transform spectroscopy(DRIFTS) verifies the augment of low-coordinated oxygen, CO₂-temperature programmed desorption(CO₂-TPD) experiment reveals that modification of Ce increases the density of basic sites on surface. Aqueous reconstructed HTc-Ce-3.2 catalyst exhibits high activity for acetone self-condensation. The conversion of acetone is 56.8%. It is 2.5 times higher than that of HTc catalyst, the selectivity of pentamers enhance significantly.

Key words: Aqueous reconstruction, Oxygen vacancy, Mixed metal oxide, Vapor self condensation of acetone, Ce modification

中图分类号:

O643.3

TrendMD:

吴斌泉, 王圣, 黄亮, 秦枫, 黄镇, 徐华龙, 沈伟. 水相重构法制备Ce改性Mg-Al复合氧化物及其在丙酮气相缩合反应中的应用. 高等学校化学学报, 2016, 37(4): 745.

WU Binquan, WANG Sheng, HUANG Liang, QIN Feng, HUANG Zhen, XU Hualong, SHEN Wei. Preparation of Ce Modified Mg-Al Mixed Metal Oxides by Aqueous Reconstruction for Vapor Self-condensation of Acetone^†. Chem. J. Chinese Universities, 2016, 37(4): 745.

图/表 9

参考文献 26

[1]	Abelló S., Medina F., Tichit D., Pérez-Ramírez J., Groen J. C., Sueiras J. E., Salagre P., Cesteros Y., Chem. Eur. J., 2005, 11, 728—739
[2]	Cosimo J. I., Díez V. K., Apesteguía C. R., Appl. Catal. A: Gen., 1996, 137, 149—166
[3]	Abelló S., Medina F., Tichit D., Pérez-Ramírez J., Rodrguez X., Sueiras J. E., Salagre P., Cesteros Y., Appl. Catal., 2005, 281, 191—198
[4]	Wang S., Wu X. W., Li H. P., Zhang R. J., Hou W. G., Chem. J. Chinese Universities, 2014, 35(9), 1982—1987
	(王爽, 兀晓文, 李海平, 张人杰, 侯万国. 高等学校化学学报,2014, 35(9), 1982—1987)
[5]	Roelofs J. C. A. A., Lensveld D. J., van Dillen A. J., de Jong K. P., J. Catal., 2001, 203, 184—191
[6]	Nakayama H., Wada N., Tsuhako M., International Journal of Pharmaceutics, 2004, 269, 469—478
[7]	Rives V., Ulibarri M. A., Coord. Chem. Rev., 1999, 181, 61—120
[8]	Winter F., Xia X. Y., Hereijgers B. P. C., Bitter J. H., van Dillen A. J., Muhler M., de Jong K., J. Phys. Chem. B, 2006, 110, 9211—9218
[9]	Cui Y. Y., Chen X. R., Journal of Hebei University of Technology, 2011, 40(3), 20—23
	(崔圆圆, 陈霄榕. 河北工业大学学报, 2011, 40(3), 20—23)
[10]	Liu Y. X., Sun K. P., Ma H. W., Xu X. L., Wang X. L., Catalysis Communications, 2010, 11, 880—883
[11]	Sun J., Yang J. Y., Li S. P., Xu X. R., Catalysis Communications, 2014, 52, 1—4
[12]	Wang Z., Fongarland P., Lu G. Z., Essayem N., J. Catal., 2014, 318, 108—118
[13]	Martin D., Duprez D., J. Phys. Chem., 1996, 100, 9429—9438
[14]	Drouilly C., Krafft J. M., Averseng F., Lauron-Pernot H., Bazer-Bachi D., Chizallet C., Lecocq V., Costentin G., Appl. Catal. A: Gen., 2013, 453, 121—129
[15]	Pérez-Ramírez J., Abelló S., van der Pers N. M., J. Phys. Chem. C, 2007, 111, 3642—3650
[16]	Bîrjega R., Pavel O. D., Costentin G., Che M., Angelescu E., Appl. Catal. A: Gen., 2005, 288, 185—193
[17]	Rodrigues E., Pereira P., Martins T., Vargas F., Scheller T., Correa J., Del Nero J., Moreira S. G. C., Ertel-Ingrisch W., De Campos C. P., Gigler A., Materials Letters, 2012, 78, 195—198
[18]	Ma C. X., Liu G., Wang Z. L., Li Y. F., Zheng J., Zhang W. X., Jia M. J., React. Kinet. Catal. Lett., 2009, 98(1), 149—156
[19]	Díez V. K., Apesteguía C. R., Di Cosimo J. I., Journal of Catalysis, 2003, 215, 220—233
[20]	Meis N. N. A. H., Bitter J. H., de Jong K. P., Ind. Eng. Chem. Res., 2010, 49(3), 1229—1235
[21]	Alvarez M. G., Pliskova M., Segarra A. M., Medina F., Figueras F., Appl. Catal. B, 2012, 113, 212—220
[22]	Urdå A., Popescu I., Cacciaguerra T., Tanchoux N., Tichit D., Marcu I. C., Appl. Catal. A: Gen., 2013, 464, 20—27
[23]	Di Cosimo J. I., Díez V. K., Xu M., Iglesia E., Apesteguía C. R., Journal of Catalysis, 1998, 178, 499—510
[24]	Kus'trowski P., Sulkowska D., Pytlowany R., Dziembaj R., React. Kinet. Catal. Lett., 2004, 81(1), 3—11
[25]	Bej S. K., Thompson L. T., Appl. Catal. A: Gen., 2004, 264, 141—150
[26]	Zamora M., López T., Gómez R., Asomora M., Meléndrez R., Applied Surface Science, 2005, 252, 828—832

Sample	Cell parameter		Particle size/nm	Sample	Cell parameter		Particle size/nm
Sample	a/nm		Particle size/nm	c/nm		a/nm	c/nm
HT	0.304	22.71	50	HT-Ce-1.6	0.304	22.84	11
HT-rh	0.304	22.72	15	HT-Ce-3.2	0.304	23.31	11
HT-Ce-0.8	0.304	22.81	12	HT-Ce-6.3	0.304	26.26	18

Sample	Cell parameter		Particle size/nm	Sample	Cell parameter		Particle size/nm
Sample	a/nm		Particle size/nm	c/nm		a/nm	c/nm
HT	0.304	22.71	50	HT-Ce-1.6	0.304	22.84	11
HT-rh	0.304	22.72	15	HT-Ce-3.2	0.304	23.31	11
HT-Ce-0.8	0.304	22.81	12	HT-Ce-6.3	0.304	26.26	18

Sample	Atomic mass fraction^a(%)		Bulk atomic ratio^a		Surface atomic ratio^b
Sample	Mg	Ce	Al	Mg/Al	Mg/Ce	Mg/Al	Mg/Ce
HTc	7.90		13.37	1.90		1.23
HTc-rh	8.76		14.33	1.84		1.00
HTc-Ce-0.8	7.69	1.18	12.88	1.88	63.67	1.09	34.82
HTc-Ce-1.6	7.96	2.20	13.14	1.86	34.84	1.34	18.61
HTc-Ce-3.2	7.67	4.15	13.18	1.93	18.53	1.36	5.27
HTc-Ce-6.3	6.43	6.41	11.21	1.96	10.20	1.49	3.49

Sample	Atomic mass fraction^a(%)		Bulk atomic ratio^a		Surface atomic ratio^b
Sample	Mg	Ce	Al	Mg/Al	Mg/Ce	Mg/Al	Mg/Ce
HTc	7.90		13.37	1.90		1.23
HTc-rh	8.76		14.33	1.84		1.00
HTc-Ce-0.8	7.69	1.18	12.88	1.88	63.67	1.09	34.82
HTc-Ce-1.6	7.96	2.20	13.14	1.86	34.84	1.34	18.61
HTc-Ce-3.2	7.67	4.15	13.18	1.93	18.53	1.36	5.27
HTc-Ce-6.3	6.43	6.41	11.21	1.96	10.20	1.49	3.49

Sample	Temperature/℃		Weak basicity/ (mmol·g^-1)	Strong basicity/ (mmol·g^-1)	Surface area/ (m²·g^-1)	Pore volume/ (cm³·g^-1)	WBPC^a/ (mmol·g^-1)	SBPC^b/ (mmol·g^-1)
Sample	First peak	Second peak	Weak basicity/ (mmol·g^-1)	Strong basicity/ (mmol·g^-1)	Surface area/ (m²·g^-1)	Pore volume/ (cm³·g^-1)	WBPC^a/ (mmol·g^-1)	SBPC^b/ (mmol·g^-1)
HTc	109	234	0.082	0.096	127	0.19	0.082	0.096
HTc-rh	105	257	0.093	0.103	188	0.41	0.093	0.103
HTc-Ce-0.8	99	244	0.105	0.116	220	0.57	0.108	0.120
HTc-Ce-1.6	102	250	0.103	0.125	178	0.48	0.110	0.133
HTc-Ce-3.2	105	253	0.105	0.144	137	0.47	0.119	0.163
HTc-Ce-6.3	101	271	0.104	0.134	146	0.42	0.131	0.169