掺杂方法对Cu-OMS-2催化氧化甲苯性能的影响
Effect of doping methods of Cu-OMS-2 on catalytic oxidation of toluene
-
摘要: 分别采用前掺杂法(PI)、离子交换法(IE)和浸渍法(IM)合成了过渡金属Cu掺杂的催化剂Cu-OMS-2,通过XRD、BET、XPS、H2-TPR等手段对催化剂的结构进行表征,并测试催化剂对甲苯的催化燃烧性能.XRD结果显示,全部掺Cu样品与单纯OMS-2晶相峰相同;XPS结果表明,Cu掺杂有效调控了Mn3+/Mn4+的比例,催化剂表面形成不同数量氧空位,其中前掺杂法和离子交换法制备的催化剂表面生成了更多的氧空位;H2-TPR结果显示Cu掺杂降低了催化剂还原温度,且前掺杂法和离子交换法制备的催化剂的还原温度低于浸渍法合成的样品.因此,前掺杂法和离子交换法合成的催化剂在甲苯催化氧化中显示出较高的催化活性.Abstract: Cu-OMS-2 catalysts were synthesized by the methods of pre-incorporation(PI), ion exchange(IE) and impregnation(IM), respectively. The structures of the catalysts were characterized by X-ray diffraction (XRD), N2 adsorption/desorption (BET), X-ray photoelectron spectroscopy (XPS) and H2 temperature program reduction (H2-TPR). The catalytic performance of the catalysts for toluene combustion was investigated. The XRD results showed that all the Cu doped samples were identical to the pure OMS-2 crystal phase. The XPS results suggested that the ratio of Mn3+/Mn4+ and the amounts of oxygen vacancies of the catalyst were adjusted by Cu doping. The amounts of oxygen vacancies in the Cu-OMS-2-PI and Cu-OMS-2-IE were higher than that of Cu-OMS-2-IM. H2-TPR results indicated that the reduction temperature of OMS-2 decreased by Cu doping, and the catalyst prepared by PI and IE method showed a lower reduction temperature than the catalyst prepared by IM method. Therefore, the catalysts prepared by PI and IE method showed higher catalytic activities for toluene combustion than the catalyst prepared by IM method.
-
Key words:
- Cu-OMS-2 /
- toluene /
- catalytic oxidation /
- pre-incurporation /
- ionexchange(IE) /
- impregnation(IM)
-
-
[1] CHEN H H, ZHANG H P, YAN Y. Gradient porous Co-Cu-Mn mixed oxides modified ZSM-5 membranes as high efficiency catalyst for the catalytic oxidation of isopropanol[J]. Chemical Engineering Science, 2014, 111:313-323. [2] 李永峰, 刘祖超, 麦荣坚. Pd基无涂层整体式催化剂上甲苯催化燃烧净化研究[J]. 燃料化学学报, 2011, 39(9):712-716. LI Y F, LIU Z C, MAI R J. Study on catalytic combustion of toluene over Pd-based uncoated monolithic catalyst[J]. Journal of Fuel Chemistry and Technology, 2011, 39(9):712-716(in Chinese).
[3] 孙忠. 钙钛矿催化剂催化燃烧VOCs的活性和抗氯性研究[D]. 杭州:浙江工业大学, 2010. SUN Z. Study on activity and chlorine resistance of VOCs catalyzed by perovskite catalyst[D]. Hangzhou:Zhejiang University of Technology, 2010(in Chinese). [4] HERNáNDEZA W Y, CENTENOA M A, ROMERO-SARRIAA F, et al. Modified cryptomelane-type manganese dioxide nanomaterials for preferential oxidation of CO in the presence of hydrogen[J]. Catalysis Today, 2010, 157:160-165. [5] SANTOS V P, PEREIRA M F R, ORFAO J J M, et al. The role of lattice oxygen on the activity of manganese oxides towards the oxidation of volatile organic compounds[J]. Applied Catalysis B-Environmental, 2010, 99(1-2):353-363. [6] WANG R H, LI J H. Effects of precursor and sulfation on OMS-2 catalyst for oxidation of ethanol and acetaldehyde at low temperatures[J]. Environmental Science & Technology, 2010, 44(11):4282-4287. [7] HOU J T, LIU L L, LI Y Z, et al. Tuning the K+ concentration in the tunnel of OMS-2 nanorods leads to a significant enhancement of the catalytic activity for benzene oxidation[J]. Environment Science Technology, 2013, 47:13730-13736. [8] KINGONDU C K, OPEMBE N, CHEN C H, et al. Manganese oxide octahedral molecular sieves (OMS-2) multiple framework substitutions:a new route to OMS-2 particle size and morphology control[J]. Advanced Functional Materials, 2011, 21(2):312-323. [9] CHEN X, SHEN Y F, SUIB S L, et al. Characterization of manganese oxide octahedral molecular sieve (M-OMS-2) materials with different metal cation dopants[J]. Chemistry of Materials, 2002, 14(2):940-948. [10] SUN M, YU L, YE F, et al. Transition metal doped cryptomelane-type manganese oxide for low-temperature catalytic combustion of dimethyl ether[J]. Chemical Engineering Journal, 2013, 220:320-327. [11] 赵海霞, 叶青, 张玉, 等. 氧化锰八面体分子筛负载Cu催化剂催化氧化性能研究[J]. 环境污染与防治, 2014, 36(4):33-37. ZHAO H X, YE Q, ZHANG Y, et al. Study on catalytic oxidation of Cu catalyst supported on manganese oxide octahedral molecular sieves[J]. Environmental Pollution and Prevention, 2014, 36(4):33-37(in Chinese).
[12] LIU J, MAKWANA V, CAI J, et al. Effect of alkali metal and ammonium cation templates on nanofibrous cryptomelane-type manganese oxide octahedral molecular sieves(OMS-2)[J]. Journal of Physical Chemistry B, 2003, 107:9185-9194. [13] HOU J T, LI Y Z, LIU L L, et al. Effect of giant oxygen vacancy defects on the catalytic oxidation of OMS-2 nanorods[J]. Journal of Material S Chemistry A, 2013, 1:6736-6741. [14] XIA G G, YIN Y G, WILLIS W S, et al. Efficient stable catalysts for low temperature carbon monoxide oxidation[J]. Journal of Catalysis, 1999, 185(1):91-105. [15] LIANG S H, BULGAN F T G, ZONG R L, et al. Effect of phase structure of MnO2 nanorod catalyst on the activity for CO oxidation[J]. Journal of Physical Chemistry C, 2008, 112(14):5307-5315. -

计量
- 文章访问数: 1230
- HTML全文浏览数: 1159
- PDF下载数: 218
- 施引文献: 0