负载Ni催化剂用于乙二醇蒸汽重整制氢催化性能研究

采用等体积浸渍法和共沉淀法制备了Ni催化剂,在固定床反应器上考察了Ni负载量、焙烧温度、反应温度等因素对乙二醇低温重整制氢反应活性和选择性的影响。应用X射线衍射、氮物理吸附、H₂程序升温还原等技术对负载型Ni催化剂进行了表征。结果表明,共沉淀法制备的Ni/CeO₂催化剂具有较小的NiO颗粒与CeO₂载体颗粒粒径,催化活性较高。添加少量氧化钴到Ni/CeO₂催化剂中可使H₂收率达72.6%,EG转化率达93.1%。在CeO₂中添加Al₂O₃能提高负载Ni催化剂的活性,乙二醇转化率达94.0%,H₂收率达67.0%;但添加SiO₂则使其活性明显变差。

Hydrogen production from steam reforming of ethylene glycol over supported nickel catalysts

A series of nickel catalysts were prepared by the impregnation and co-precipitation methods and characterized by X-ray diffraction, nitrogen physisorption, and H₂ temperature-programmed reduction. The effects of nickel loading, calcination temperature, reaction temperature, support modification and cobalt oxide addition on the catalytic activity and selectivity to H₂ in the steam reforming of ethylene glycol were investigated. The results indicate that the nickel catalyst prepared by co-precipitation has smaller particle size and relatively higher activity in comparison with the catalyst prepared by impregnation. Adding a small amount of cobalt oxide to the Ni/CeO₂ catalysts can enhance the catalytic activity; over the Ni-Co bimetallic catalyst, the yield of hydrogen reaches 72.6%. Modifying CeO₂ with Al₂O₃, TiO₂ and ZrO₂ also has a certain influence on the catalytic activity and the Ni/CeO₂-Al₂O₃ catalyst exhibits the highest activity, with an ethylene glycol conversion of 94% to gaseous products and a hydrogen yield of 67.0%. However, Ni/CeO₂-SiO₂ shows a very low activity in spite of its large surface area and pore volume.