ZrO2-Al2O3复合载体对镍基催化剂甲烷化性能的影响

摘要

Ni/ZrO2-Al2O3 catalysts were prepared by multi-step wet impregnation method and characterized by N2 physisorption,X-ray diffraction (XRD),temperature-programmed reduction (TPR),temperature-programmed desorption (TPD) and temperature-programmed oxidation (TPO) techniques. The influence of zirconia loading on the reactivity of alumina supported nickel catalysts for CO methanation with low H2/CO ratio has been investigated. The results revealed that the addition of an intermediate content of ZrO2 improved the reducibility and dispersion of Ni species by weakening the interaction between nickel and support , which is responsible for the enhanced catalytic performances. Furthermore,it was shown that the addition of ZrO2 in Ni/Al2O3 catalysts effectively inhibited the formation of low active C species,resulting in a better coking resistance and higher catalytic stability.%采用分步浸渍法制备了不同ZrO2载量的Ni/ZrO2-Al2O3催化剂，利用N2物理吸附、X射线衍射（XRD）、H2程序升温还原（H2-TPR）、H2程序升温脱附（H2-TPD）、程序升温氧化（TPO）等手段对催化剂的结构进行表征，并考察了其在低H2/CO比（H2/CO约为1）下CO甲烷化的催化性能。结果表明，ZrO2助剂可削弱NiO与载体Al2O3间的相互作用，抑制镍铝尖晶石的生成。适量ZrO2的引入有助于提高活性组分Ni的还原度和分散度，对催化剂的甲烷化性能有促进作用。通过分析反应后催化剂上的积炭性质，发现ZrO2的加入能有效地抑制低活性碳物种的生成，提高催化剂的抗积炭能力，从而改善催化剂的稳定性。