催化学报

催化学报 ›› 2012, Vol. 33 ›› Issue (5): 863-869.DOI: 10.3724/SP.J.1088.2012.11204

• 研究论文 • 上一篇    下一篇

单相碳化铁的制备及其表面吸附性质

王瑞雪1,2,3, 吴宝山1,3,*, 李永旺 1,3   

  1. 1中国科学院山西煤炭化学研究所煤转化国家重点实验室, 山西太原030001; 2中国科学院研究生院, 北京 100049; 3中国科学院山西煤炭化学研究所煤间接液化国家工程实验室, 山西太原 030001
  • 收稿日期:2011-12-01 修回日期:2012-01-10 出版日期:2012-05-09 发布日期:2012-05-09

Synthesis of Single-Phase Iron Carbides and Their Adsorption Performance

WANG Ruixue1,2,3, WU Baoshan1,3,*, LI Yongwang1,3   

  1. 1State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001, Shanxi, China; 2Graduate University of Chinese Academy of Sciences, Beijing 100049, China; 3National Engineering Laboratory for Coal Indirect Liquefaction, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001, Shanxi, China
  • Received:2011-12-01 Revised:2012-01-10 Online:2012-05-09 Published:2012-05-09

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1519

被引次数

8

摘要： 在不同 CO 分压下制备了 ε-Fe2C, χ''-Fe5C2 和 θ-Fe3C 等系列单相碳化铁, 经钝化处理后采用低温 N2 物理吸附、穆斯堡尔谱、激光拉曼光谱和程序升温脱附技术进行了详细的表征. 结果发现, 碳化气氛, 尤其是碳化温度对所得碳化铁结晶度有所影响. 碳化铁表面的积碳程度随碳化气氛中 CO 分压的升高而增高, 而随碳化温度的升高呈抛物线形式增高; 不同碳化条件下生成的碳化铁晶型和表面积碳的差异导致其织构性质及其吸附 CO 的能力不同, 低温 (200 oC) 碳化生成的 Fe2C 表面解离吸附 CO 的能力显著强于其他碳化铁; 低碳气氛中生成的 Fe3C 上 CO 的解离脱附量最大; 其他条件下生成的碳化铁因表面吸附活性位的破坏和大量沉积碳的生成使得解离吸附 CO 的能力较弱.

关键词: 单相, 碳化铁, 积碳, 一氧化碳, 吸附性能

Abstract: A series of iron carbides with single-phases, including ε-Fe2C, χ''-Fe5C2, and θ-Fe3C, were synthesized in different carbonization gases either in higher or lower CO part pressure. After passivation, the iron carbides were characterized by N2 physical adsorption, Mössbauer spectroscopy, temperature-programmed desorption, and laser Raman spectroscopy. The effects of carbonization gases and temperature on the structure properties of the iron carbides were obvious, especially for carbonization temperature. Carbonization gas with higher CO part pressure and higher temperature both enhances the carbon deposition on the iron carbides surface. It is interesting to note that the carbon deposition increases firstly with the rise of temperature and then decreases. The differences in structure and carbon deposition on iron carbides result in varied adsorption properties. Fe2C synthesized at lower temperature (200 oC) was highly susceptible to dissociative adsorption of CO on its surface, while Fe3C prepared under lower CO part pressure showed the highest desorption of adsorbed CO. The ability of dissociative adsorption of CO on the iron carbides prepared under other condition reduces probably because of carbon deposition.

Key words: single-phase, iron carbide, carbon deposition, carbon monoxide, adsorption performance