Kinetic Study of Methane Oxidation on Pt/BN Catalyst

甲烷在Pt/BN觸媒氣化的反應動力探討

吳紀聖(Jeffrey C.S. Wu) ； 章子彬(Tzyy-Bin Jang) ； 林致安(Chih-An Lin)

《Journal of the Chinese Institute of Chemical Engineers》 33卷2期 (2002/03) Pp. 123-132

https://doi.org/10.6967/JCICE.200203.0123

摘要

使用hexagonal氧化硼(h-BN)載體支撐的白金(Pt)觸媒，進行甲烷觸媒氧化反應以研究h-BN獨特的反應動力表現。用臨界沾濕法製備0.37wt% Pt/h-BN觸媒，氧氣濃在10~80%，甲烷濃度4000-1000 ppmv的點火點(light-off temperature，在50%轉化率)約在475℃左右。內在反應動力(intrinsic kinetic)的數據是在確認沒有內外質傳和熱傳阻力的實驗下獲得，估算反應活化能大約是76 kJ/mole顯示是表面反應所控制。反應基本步驟和反應機構是以Langmuir-Hinshewood模式為基礎推導而得，以Pt/h-BN觸媒氧化甲烷，其反應次數對甲烷為一次，對氧氣則為0.25次。根據結果推測反應速率決定步驟是在白金活性基上吸附甲烷的第二個氫解離步驟。

並列摘要

The unique kinetics of hexagonal boron nitride (h-BN) supported Pt catalyst were studied via the catalytic oxidation of methane. The catalyst of 0.37 wt% Pt/h-BN catalyst was prepared using the incipient wetness method. The oxygen concentrations ranged from 10 to 80%. The light-off temperature (at 50% conversion) was approximately 475℃ under methane concentrations of 4000-1000 ppmv. The intrinsic kinetic date were carefully obtained by eliminating both external and internal resistances of mass as well as heat transfers. The apparent activation energy was estimated to be~76 kJ/mol, indicating surface reaction control. The elementary steps and reaction mechanism were established based on the Langmuir-Hinshewood model. The methane deep oxidation over Pt/h-BN was found to be first order with respect to methane and one-fourth order with respect to oxygen. The results suggested that the rate-determining step was the second hydrogen stripping of adsorbed methane on Pt active sites.

並列關鍵字

Catalytic oxidation ； Boron nitride ； Pt ； Methane ； Kinetics