摘要
采用超声浸渍法制备了费托合成Co/Zr/SiO2催化剂,考察了超声波功率对催化剂费托反应性能的影响,并运用N2物理吸附、X射线衍射、H2程序升温脱附、H2程序升温还原和透射电子显微镜对催化剂进行了表征.结果表明,超声波处理可以增大催化剂的比表面积,减小金属Co的粒径,并使其较为均匀地分散于载体表面,其中以高功率超声波作用最为显著;Co(NO3)2水溶液在高功率超声波场中,随着超声时间的延长,溶液pH值降低,使得Co–SiO2相互作用减弱,抑制了硅酸钴的生成.经高功率超声波处理的催化剂,活性金属Co在载体上分散度和还原度较高,因而催化剂的活性和稳定性较高.在493K,2MPa,H2/CO=2.0和GHSV=1000h-1反应条件下,CO初始转化率可达95.5%,反应48h时,CO转化率为90.9%.
A Co/Zr/SiO2 catalyst for Fischer-Tropsch synthesis was prepared under an ultrasound environment. The influence of different ultrasonic powers on catalyst performance was studied. The catalysts were characterized by N2 physisorption,X-ray diffraction,H2 tempera-ture-programmed desorption,H2 temperature-programmed reduction,and transmission electron microscopy. The results show that ultrasound assisted in increasing the BET surface area of the catalysts and the even the dispersion of small cobalt crystallites on the support. When higher power ultrasound was used these characteristics of the catalyst changed remarkably. The pH of the Co（NO3） 2 aqueous solution de-creased with an increase in high power ultrasound treatment time,which led to a weak interaction between the smaller cobalt particles and the silica support. In addition,less cobalt silicate was formed on the catalyst. Under the same reaction conditions,the catalyst activity and stability were superior to that of the other catalysts because of higher dispersion and reduction. For example,the initial conversion of CO was 95.5% at 493 K,2 MPa,H2/CO = 2.0,and GHSV = 1000 h-1,and it was 90.9% after 48h.
出处
《催化学报》
SCIE
EI
CAS
CSCD
北大核心
2011年第7期1156-1165,共10页
关键词
费托合成
超声浸渍
真空
钴
锆
氧化硅
Fischer-Tropsch synthesis
ultrasound impregnation
vacuum
cobalt
zirconium
silica
作者简介
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