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利用等体积浸渍法制备了氧化硅负载钴催化剂 .通过程序升温还原、氢化学吸附、氧滴定和催化活性评价等手段研究了氧化钡对Co/SiO2 的还原性能、钴分散度和颗粒度、分解甲烷活性及其稳定性等的影响 .研究结果表明 ,氧化钡明显地影响Co/SiO2 的还原性能 ;添加 2 %氧化钡提高了Co/SiO2 在中温 (4 5 0℃ )条件下的还原度 ;氧化钡的还原对Co/SiO2 还原的诱导、氧化钡与氧化硅及与氧化钴之间的相互作用是导致Co/SiO2 还原性能变化的原因 .氧化钡提高了Co/SiO2 的初活性和钴的分散度 ,降低了钴的颗粒度 ;添加 0 5 %～ 1 5 %氧化钡有利于提高Co/SiO2 的稳定性 .钴的分散度和颗粒度影响Co/SiO2的活性和稳定性 ;氧化钡的强供电效应也是提高Co/SiO2 活性和稳定性的重要因素 .甲烷分解生成的碳物种覆盖了钴活性中心 ,导致Co/SiO2 初活性下降 ;但大部分碳物种并不沉积在钴活性中心上 ,可能形成了碳纤维生长在载体和钴活性中心之间
The cobalt oxide supported silica catalyst was prepared by the same volume impregnation method.The reduction performance, cobalt dispersion and particle size of barium oxide were studied by temperature programmed reduction, hydrogen chemisorption, oxygen titration and catalytic activity evaluation. Methane activity and its stability, etc. The results show that barium oxide significantly affects the reduction performance of Co / SiO2; addition of 2% barium oxide increases the reduction of Co / SiO2 at medium temperature (405) The reduction of barium oxide contributes to the reduction of Co / SiO2, and the interaction between barium oxide, silicon oxide and cobalt oxide is the reason for the change of the reduction performance of Co / SiO2. Barium oxide increases the initial activity of Co / SiO2 and cobalt Dispersion degree decreased the particle size of cobalt. Adding 0 5% ~ 15% barium oxide was beneficial to improve the stability of Co / SiO2. Co dispersion and particle size affected the activity and stability of Co / SiO2; The strong power supply effect is also an important factor to improve the activity and stability of Co / SiO2. The carbon species formed by methane decomposition covers the active center of cobalt, resulting in the decrease of initial activity of Co / SiO2. However, most of the carbon species do not deposit in the activity of cobalt , The growth may be formed in the center between the support and cobalt as active carbon fibers