物理化学学报 >> 1994, Vol. 10 >> Issue (07): 616-622.doi: 10.3866/PKU.WHXB19940708

研究论文 上一篇    下一篇

锂在甲烷氧化偶联多元氧化物催化剂中的作用

赵震, 远松月, 于作龙   

  1. 中国科学院长春应用化学研究所,长春 130022|中国科学院成都有机化学研究所,成都 610015
  • 收稿日期:1993-03-12 修回日期:1993-07-31 发布日期:1994-07-15
  • 通讯作者: 远松月

Role of Lithium in Multicomponent Oxide Catalysts for Oxidative Coupling of Methane

Zhao Zhen, Yuan Song-Yue, Yu Zuo-Long   

  1. Changchun Institute of Applied Chemsitry, Academia Sinica, Changchun 130022|Chengdu Institute of Organic Chemistry, Academia Sinica, Chengdu 610015
  • Received:1993-03-12 Revised:1993-07-31 Published:1994-07-15
  • Contact: Yuan Song-Yue

摘要:

考察了不同Li含量对Li_xLa_(0.5)Ti_(0.5)系氧化物催化剂的甲烷氧化偶联催化性能的影响;比较了水洗前后LiLa_(0.5)Ti_(0.5)氧化物催化剂的催化活性,并通过XRD、IR、XPS和BET等方法时催化剂进行表征。确认了Li在含稀土、过渡金属多元氧化物中的作用。其中,表面Li的作用是缩小催化剂的比表面积,覆盖表面深度氧化活性位,提高C_2选择性;体相Li的作用是部分取代Ti~(3+)进入LaTiO_3晶格形成LaTi_(1-y)LiyO_(3-λ)活性相,产生甲烷氧化偶联Li~+-O~--Ti~(3+)缺陷簇。
(注:Li_xLa_(0.5)Ti_(0.5)和LiLa_(0.5)Ti_(0.5)表示该系列氧化物催化剂制备时的各金属元素的配比。用来表示催化剂的名称,并不表示实际存在的物相,以下类同,下面出现时,不再加以说明。)

关键词: 甲烷氧化偶联, 催化剂, 锂钛镧氧化物, 锂的作用

Abstract:

The effect of Li content in a series of multicomponent oxides Li_xLa_(0.5)Ti_(0.5) for methane oxidative coupling has been studied. The catalytic activities of LiLa_(0.5)Ti_(0.5) catalyst befroe and after washing with boiling water have been compared. The surface and bulk structure of the catalysts were characterized by means of XRD、XPS、IR、BET and so on. The results clearly indicated that the role of Li on the surface is to decrease the sruface area of the catalysts and to cover the deep oxidative active sites thus increasing the C_2 selectivity. However, the role of lithium in the bulk is to produce active phase LaTi_(1-y)Li_yO_(3-λ) in which the defect clusters Li~+-O~--Ti~(3+) act as the active sites for methane oxidative coupling.

Key words: Methane oxidative coupling, Catalyst, Titanium-lanthanum-lithium, Role of lithium