【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。更多还原

【Abstract】 The effects of different precursors for CuO on the catalytic properties of 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 Fe²⁺, 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.更多还原