Co/AlPO4-5催化剂中Co的状态及其作用 |
STATES AND ACTION OF COBALT IN Co/AlPO4-5CATALYST |
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摘要: 本文用IR,TEM,FABMS,ESCA,XRD以及还原度的测定等方法,描述了Co/AlPO4-5上Co3O4在氢作用下变成Co°,CoO以及未还原的Co3O4三种状态的还原过程和钴的颗粒分布的变化,并表明在还原过程中,可能有钴的簇状物生成,导致B酸形成。 |
关键词: 磷酸铝分子筛 钴的氧化物 钴 |
基金项目: |
Abstract: The TEM ESCA has been used to study of Co3O4 in Co/ AlPO4-5 catalyst in the process of reduction by H2 and the particle size distribution of cobalt before and after reduction by H2was also studied. The results showed that the states of cobalt were presented as Co3O4 before reduction by H2 and after reduction by H2 they existed in Co, CoO and Co3O4 three states. The sequence of reduction was Co3O4-CoO-Co°. CoO-Co° is the rate determining step. The results also showed that before reduction its particle size distribution is in a wide range, andthe average particle size is -6.9nm. After reduction its particle size disribution is more homogeneous and the average particle size is -3.2nm.The FAB-MS results showed that at 773K in the process of reduction cobalt species were dislodged from the channels of catalyst to external surface and surface can become very rich in cobalt of cobalt oxide.The determination and calculation of the reduction degree give us a conclusion that the reduction process is a typic touching sphere model and the reduction degree is difficult to reach 100% under our experimental condition.From all of the former experiment results, we suggest that the cobalt clusters may be formed after reduction by H2, which induce the production of Bronsted acid site so that n-hexane cracking reaction can occur on this catalyst and carboniogenic products distribution exists. The peak of Bronsted acid is also found in the IR spectra of the reducted Co / AlPO4-5. |
Keywords: AIPO4 molecular sieve cobalt oxide cobalt |
投稿时间:1988-04-26 |
摘要点击次数: 1368 |
全文下载次数: 1438 |
须沁华,董家騄,陈钊.Co/AlPO4-5催化剂中Co的状态及其作用[J].无机化学学报,1990,6(1):64-69. |
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