NiO/SnO_2-ZrO_2催化剂的制备及甲烷燃烧催化性能的研究

PREPARATION OF NiO/SnO_2-ZrO_2 SERIES CATALYSTS AND THEIR CATALYTIC PERFORMANCE IN METHANE COMBUSTION

利用正交分析,通过溶胶凝胶-超临界干燥及复合浸渍的方法制备了NiO SnO2 ZrO2催化剂,进行了活性评价,考察了前驱物、NiO、SnO2含量及制备方法对催化剂活性及稳定性的影响,并采用XRD、TEM对催化剂进行了表征分析,结果表明:NiO SnO2 ZrO2催化剂具有良好的甲烷燃烧催化性能(t100%=640℃),其活性、稳定性与制备参数密切相关,其中NiO含量是影响催化剂活性、稳定性的最主要参数,它对催化剂稳定性和活性的影响规律正相反;SnO2组分的添加使ZrO2单斜相稳定,对催化剂起到了良好的稳定化作用,发现当SnO2含量在6mol%左右时,催化剂具有较好的稳定性;对于制备方法,在凝胶前加入活性组分有利于催化剂的高活性,而在凝胶后加入活性组分,则有利于催化剂保持较好的稳定性;活性组分前驱物对催化剂性能影响不大,采用Ni(NO3)2作为前驱物较为合适。

Catalysts prepared by different approaches show different properties and different catalytic performance The effects of precursor metal, content of precursor metal, preparing method as well as SnO2 content on the catalytic activity and stability of methane combustion were investigated Solgel method involving supercritical fluid drying technique was employed for the preparation of ZrO2based materials Activity evaluation of methane combustion was executed The results indicated that NiO/SnO2ZrO2 was a kind of proper catalyst in methane combustion, and most of catalysts led to the full conversion of methane at about 700?℃ without the production of CO NiO content is the most important preparation parameter for activity and thermal stability of catalyst, but NiO content influenced the activity and thermal stability of catalysts in an opposite way Xray diffraction(XRD) revealed Sn might be advantage of the high temperature stability of ZrO2 powder 