摘要
用Ｏ２－ＴＰＤ、ＣＯ２－ＴＰＤ和ＴＰＲ－ＴＰＯ技术研究了Ｌｉ－Ｌａ－Ｍｎ／ＴｉＯ２（Ⅰ）和Ｌｉ－Ｌａ－Ｍｎ－Ｗ／ＴｉＯ２（Ⅱ）甲烷氧化偶联催化剂对氧的吸附能力、表面酸碱性和表面氧化－还原性能，并结合这两个催化剂对甲烷氧化偶联反应的性能进行了讨论。Ｏ２－ＴＰＤ、ＣＯ２－ＴＰＤ和ＴＰＲ－ＴＰＯ结果显示出，Ⅱ号催化剂对氧的吸附能力比Ⅰ号催化剂强得多；Ⅰ号和Ⅱ号催化剂都具有较强的碱性位，但Ⅱ号催化剂的强碱性位数量比Ⅰ号催化剂多，而且出现强碱性位的位置显著地向低温方向移动，同时Ⅱ号催化剂的氧化能力也比Ⅰ号催化剂强。从而使得Ⅱ号催化剂比Ⅰ号催化剂具有更高的催化活性和Ｃ２烃收率，最佳反应温度也降低了８０℃，同时最佳空速也显著增大。Ⅱ号催化剂比Ⅰ号催化剂性能更加优越。
sing O2-TPD (O2-temperature programmed desorption), CO2-TPD, and TPR-TPO (temperature programmed reduction-oxi-dation) technologies, the adsorption capacities for O2, surface aciditybasicity, and surface ox-idation-reduction properties of Li-La-Mn/TiO2 (Ⅰ) and Li-La-Mn-W/TiO2 (Ⅱ) are studied,and the performances of these two catalysts in oxidative coupling of methane also discussed.The results show that catalyst Ⅱ exhibits much stronger adsorbability for O2 than Ⅰ.There exist strong basic sites on both Ⅰ and Ⅱ, but the quantity of said sites on Ⅱ is larger than of Ⅰ. Besides, the oxidation capacity of Ⅱ is higher than of Ⅰ. As a result, catalyst Ⅱ gives higher catalytic activity and higher yield of C2 hydrocarbons than Ⅰ while the reaction temperature can be decreased by 80℃, and the optimum space velocity significantly increased. Catalyst Ⅱ is advantageous over Ⅰ for oxidative coupling of methane.
出处
《天然气化工—C1化学与化工》
CAS
CSCD
北大核心
1995年第3期10-13,共4页
Natural Gas Chemical Industry
基金
四川省科委应用基础基金
关键词
催化剂
甲烷
氧化偶联
锂
镧
锰
钨
钛
添加物
catalyst methane
oxidative coupling O_2-TPD
CO_2-TPD
TPR-TPO
