催化学报

催化学报 ›› 2007, Vol. 28 ›› Issue (9): 789-793.

• 研究论文 • 上一篇    下一篇

BaF2/La2O3催化剂上甲烷氧化偶联反应活性氧物种的原位红外光谱

王丽华1,2,伊晓东1,翁维正1,万惠霖1   

  1. 1 厦门大学固体表面物理化学国家重点实验室, 化学化工学院化学系, 福建厦门 361005; 2 福建师范大学化学与材料学院, 福建福州 350007
  • 收稿日期:2007-09-25 出版日期:2007-09-25 发布日期:2011-09-28

In Situ Infrared Spectroscopy of Active Oxygen Species for Oxidative Coupling of Methane over BaF2/La2O3 Catalyst

WANG Lihua1,2, YI Xiaodong1, WENG Weizheng1*, WAN Huilin1*   

  1. 1 State Key Laboratory of Physical Chemistry of Solid Surfaces; Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, Fujian, China; 2 College of Chemistry and Materials Science, Fujian Normal University, Fuzhou 350007, Fujian, China
  • Received:2007-09-25 Online:2007-09-25 Published:2011-09-28

PDF

1038

被引次数

3

摘要： 用原位红外光谱研究了BaF2/La2O3催化剂上甲烷氧化偶联反应的活性氧物种. 结果表明,催化剂经O2预吸附后,在1108～1118cm-1处出现超氧物种O-2的O-O键伸缩振动峰. 经18O2同位素交换实验后,原1108～1118cm-1处谱峰的强度减弱,同时在1086和1051cm-1处出现(O18O)-物种和18O-2物种的吸收峰. 同位素交换实验进一步确证了1108～1118cm-1处谱峰确为O-2物种的吸收峰. 在700 ℃下, O-2物种能够活化CH4生成C2H4, 而且O-2物种的消耗量和C2H4的生成量呈很好的消长对应关系. 超氧物种O-2是BaF2/La2O3催化剂上甲烷氧化偶联反应的活性氧物种.

关键词: 同位素交换, 超氧物种, 红外光谱, 氧化偶联, 甲烷, 氟化钡, 氧化镧

Abstract: In situ IR spectroscopy was used to study the superoxide species (O-2) for oxidative coupling of methane (OCM) over the BaF2/La2O3 catalyst. After the pretreatment of the catalyst with O2, the IR peak at 1108-1118 cm-1appeared, which was assigned toO-Obond stretching vibration in O-2 species. After the introduction of18O2isotope, the IR peak at 1108-1118 cm-1was weakened, and the absorption peaks appeared at1086and1051cm-1, which was consistent with the assignment of theO-18Obond and18O-18Obond stretching vibrations in the superoxide species, respectively. At 700 ℃, the superoxide species could react with CH4, accompanied by the formation of gas phase C2H4. A good correlation between the rate of O-2 consumption and the rate of C2H4 formation was observed, so the superoxide species was believed to be responsible for the OCM reaction over the BaF2/La2O3 catalyst.

Key words: isotopic exchange, superoxide species, infrared spectroscopy, oxidative coupling, methane, barium fluoride, lanthanum oxide