铈改性CuMn/Al_(2)O_(3)/堇青石整体催化剂的甲苯催化燃烧性能研究

Catalytic combustion of toluene over cerium modified CuMn/Al2O3/cordierite monolithic catalyst

本研究以堇青石为载体,采用超声浸渍法制备了一系列CuMnCe_(x)/Al_(2)O_(3)/堇青石整体式催化剂,同时,通过N_(2)吸附-脱附、XRD、SEM、EDX、H_(2)-TPR、O_(2)-TPD、XPS和EPR等方法对样品的物理、化学性质进行了系统的表征分析。实验结果表明,CuMnCe_(x)/Al_(2)O_(3)/堇青石整体式催化剂中的Ce含量明显影响甲苯催化燃烧性能。其中,CuMnCe_(2)/Al_(2)O_(3)/堇青石整体式催化剂对甲苯氧化具有最高活性,当甲苯浓度为1 g/L、空速为78000 mL/(g·h)、温度为263℃时甲苯转化率达到90%,究其原因为CeO_(2)在CuMnO_(x)上分散均匀,不仅提高了氧空位的浓度和氧物种的迁移率,还增强了催化剂的低温还原性。同时,CuMnCe_(2)/Al_(2)O_(3)/堇青石整体式催化剂在长期评价和循环测试中呈现良好的稳定性。

Catalytic combustion is an effective approach to remove volatile organic compounds,in which the development of highly active and durable catalyst is extremely crucial.Herein,a series of CuMnCe_(x)/Al_(2)O_(3)/cordierite monolithic catalysts were synthesized by using the ultrasonic-assisted impregnation method.The physicochemical properties were comprehensively characterized via the BET,XRD,SEM,EDX,H2-TPR,O2-TPD,XPS and EPR techniques.The results showed that the catalytic activity of CuMnCe_(x)/Al_(2)O_(3)/Cor for toluene combustion was strongly affected by the Ce content.The CuMnCe_(2)/Al_(2)O_(3)/Cor monolithic catalyst showed the best catalytic activity with toluene conversion of 90%at 263°C under toluene concentration of 1 g/L and space velocity of 78000 mL/(g·h).Meanwhile,the well-dispersed CeO_(2) in the CuMn matrix not only improved the content of oxygen vacancies and the mobility of oxygen species,but also enhanced the low-temperature reducibility of the catalyst.Moreover,the CuMnCe_(2)/Al_(2)O_(3)/Cor monolithic catalyst exhibited an excellent stability in the long-term test and cycle ability test.