摘要
报道了未担载的氧化钴与担载在SiO2 和Al2 O3 上的氧化钴的乙烷氧化脱氢行为 ,发现未担载的氧化钴在15 0℃的低温下就有活性 .XRD研究表明 ,Co3 O4 为活性晶相组分 ,其含量与催化剂的焙烧温度密切相关 ,经 5 0 0℃和 10 0 0℃焙烧的未担载的氧化钴中Co3 O4 晶相分别占 10 0 %和 6 6 % .对于担载型氧化钴催化剂 ,载体与氧化钴间的相互作用以及不同的氧化钴担载量导致催化性能发生明显改变 .氧化钴与载体间的作用越强 ,催化活性越低 .Co3 O4 也是担载型氧化钴催化剂的活性晶相 .催化剂的O2 TPD MS和H2 TPR研究结果表明 ,反应的活性氧物种为在低温下易脱除和易还原并具有较高流动性的可动氧 .
The catalytic behavior for oxidative dehydrogenation of ethane to ethylene (ODHE) has been investigated over unsupported and supported cobalt oxides. Ethylene is found at a low temperature of 150 ℃ over unsupported cobalt oxide calcined at 500 ℃ in which the only crystallized phase detected by XRD is Co 3O 4 spinel. As the calcination temperature increasing from 500 ℃ to 1?000 ℃, the mixed crystallized phases of Co 3O 4 and CoO are detected, and the catalytic activity decreases. It has been observed that an appreciable decrease of the catalytic activity is due to the interaction between cobalt oxide and support over supported cobalt oxide catalysts, such as Co/SiO 2 and Co/γ Al 2O 3. O 2 TPD MS and H 2 TPR results reveal a good relationship among the temperature of desorption of the mobile oxygen species in the active phase of catalysts, the temperature of starting reduction of catalysts and the initial reaction temperature of ODHE. These experimental results suggest strongly that the mobile oxygen species is the active oxygen species for ODHE on this type of catalysts.
出处
《催化学报》
SCIE
CAS
CSCD
北大核心
2000年第3期204-208,共5页
关键词
乙烷
氧化脱氢
乙烯
可动氧物种
钴基催化剂
cobalt oxide, ethane, oxidative dehydrogenation, ethylene, mobile oxygen species
