pH值对共沉淀法制备高温甲烷化催化剂性能的影响

采用共沉淀法,制备沉淀过程pH分别为6~7、7~8和8~9的Ni-Mg-Al-O高温甲烷化催化剂,考察pH值对催化剂性能的影响。采用N2低温吸附、XRD、H2-脉冲化学吸附以及H2-TPR(H2-程序升温还原)对样品进行表征。结果表明,沉淀过程pH为7~8时,样品的比表面积最大,活性组分还原后不易形成大晶粒,活性组分与载体组分间的相互作用适宜,具有较好的初始活性与高温水热稳定性。

Influences of pH on catalytic performance of high temperature methanation catalysts prepared by co-precipitation methods

Hight temperature methanation catalysts Ni-Mg-Al-O were prepared by co-precipitation methods.The effects of pH values during precipitation which were 6-7,7-8 and 8-9 on catalytic performance of the catalysts were investigated.The catalysts were characterized by N₂-physisorption,XRD,H₂ pulse chemisorption and H₂-TPR.The results indicated that the specific surface areas of catalysts with precipitation pH values of 7-8 were largest.Furthermore,NiO particles were more likely to form smaller Ni particles when catalysts were reduced.Interaction between active components and carriers was moderate.Eventually,the catalysts with precipitation pH values of 7-8 showed better low temperature activity and high temperature hydrothermal stability.