摘要
考察了CuO的不同前驱体对铁铬系CO高温变换催化剂反应性能的影响,研究发现,CuO助剂可改善催化剂的低温活性,以硝酸铜的加入形式效果较为显著。对样品进行了XRD、BET、H2-TPR和XPS表征,结果表明,CuO助剂进入了Fe3O4的反尖晶石结构的八面体空隙,置换Fe2+与Fe3O4发生相互作用,改变了催化剂的还原特性,使Fe2O3还原为Fe3O4的还原温度降低了100℃左右。铜在催化剂的表面以Cu(OH)2、CuO和Cu2O三种形态存在,因Cu2+取代Fe2+的八面体配位单元,致使配位场稳定化能降低,催化剂表面容易产生O2-缺位,所产生的新的活性中心极易吸附OH-,使催化剂在低汽气比条件下参与CO变换反应,具有高活性且遏制烃类副产物的生成。
The effects of different precursors for CuO on the catalytic properties ot Fe-Cr-based CO high-temperature shift （HTS） catalyst were investigated. It was shown that CuO improved low-temperature activity of the catalyst and doping of CuO as copper nitrate was preferable. The catalysts were characterized by XRD, BET, H2-TPR and XPS. The results showed that the incorporation of CuO improved reduction properties of the catalysts, resulting in lowering of the reduction temperature for Fe2O3 by about 100℃. Most copper species were dispersed in the form of Cu（OH）2, CuO, Cu2O on surface of the catalysts. Some Cu ions imbedded into interstice of the octahedron for Fe3O4 with reverse spinel structure and partly replaced Fe^2＋ , leading to decrease of the octahedron ligand field stabilization energy. O2-vacancies were hence formed more easily on surface of the catalysts, and the new active sites thus formed was liable to absorb OH^-, which contributed to their higher activity for water gas shift reaction （WGSR） under low stream/gas ratio and hindered formation of undesirable hydrocarbons.
出处
《工业催化》
CAS
2005年第8期24-28,共5页
Industrial Catalysis
基金
福建省重点科技攻关项目资助(97004)
福州大学科技发展基金资助项目(2004-XY-05)
关键词
CO高温变换催化剂
CuO助剂
低温活性
CO high-temperature shift（HTS） catalyst
CuO promoter
low-temperature activity
