摘要
用固定床流动反应装置及ＴＰＲ、ＴＰＤ、ＸＲＤ、ＸＰＳ、ＴＥＭ等技术考察了因热处理温度不同而具有不同Ｎｉ－γ－Ａｌ_２Ｏ_３间相互作用的Ｎｉ／γ－Ａｌ_２Ｏ_３催化剂的甲烷、二氧化碳重整活性、还原性能、吸附性能、表面化学形态和抗积炭性能等。结果表明，低温热处理的催化剂具有易于还原、低温活性较高和抗积炭性能差的特性，经高温热处理的催化剂，由于Ｎｉ－γ－Ａｌ_２Ｏ_３间强的相互作用而使催化剂表面几乎全部形成了难以还原的“ＮｉＡｌ_２Ｏ_３”表面尖晶石，这虽然在一定程度上降低了催化剂的低温活性，但却使其抗积炭性能大为改观，尤其在反应温度大于７５０℃时，还可表现出与低温热处理催化剂趋于等同的高活性，实验中还观察到催化剂表面的积炭主要以空心炭丝的形式存在。
Ni/γ-Al2O3 catalysts with difference metal-support interaction were prepared by the calcination of Ni/γ-Al2O3 fresh catalyst in air at various temperatures. The reaction of reforming CH4 with CO2 was carried out in the fixed- bed reactor.The reactivity was considered in conjunction with the results of TPR,TPD,XRD,XPS and TEM.It was discovered that the catalysts calcined at high tempertures have lower activity in the lower temperature range and exhibit much better resistance to carbon deposition than those calcined at low temperatures. This is due to the presence of strong metal-support interaction when the catalyst was treated at high temperatures, and the formation of NIAl2O4 surface spinel as the main compeition on the surface of γ-Al2O3 which is difficult to be reduced. It is interesting to note that when the reaction temperature reaches above 750℃, all catalysts mentioned above tend to exhibit the same activity. Moreover,it was observed that during this reaction, only filamentary carbon with a hollow inner channel was formed. The active component of this catalyst,Ni, was pushed to the tip of these carbon filaments.
出处
《分子催化》
EI
CAS
CSCD
1994年第3期181-190,共10页
Journal of Molecular Catalysis(China)
基金
山西省青年科学基金
关键词
催化剂
甲烷
二氧化碳
镍
氧化铝
Ni/Al_2O_3 Catalyst, Methane, Carbon dioxide, Reforming
