摘要
采用共浸渍法制备了NiO-MoO_3/Al_2O_3催化剂,利用N_2物理吸附、XRD、H_2-TPR、H_2-TPD和TG等手段对催化剂的结构和性质进行表征,并考察了其在低H_2/CO摩尔比(约为1)和微量硫(5μg/g)的条件下进行CO甲烷化的催化性能。结果表明,MoO_3的引入能减弱Ni物种与载体间的强相互作用,提高催化剂的还原性能,增加Ni活性中心数。随着MoO_3质量分数的增加,催化剂的甲烷化性能先升高后降低,在MoO_3质量分数为3%时甲烷化性能最佳。积碳和硫中毒是催化剂失活的主要原因,适量MoO_3的添加能提高催化剂对H_2的吸附能力,增强催化剂的抗积碳性能,同时还能缓解硫中毒引起的失活,从而明显改善催化剂的稳定性。
The Ni O-MoO_3/ Al_2O_3 catalysts are prepared by co-impregnation method and characterized by N_2 physisorption,XRD,H_2-TPR,H_2-TPD and TG techniques. The influence of Mo O_3 loading on the catalytic activities of the catalysts for CO methanation with low H_2/CO ratio and trace H_2 S has been investigated. The results show that the presence of Mo O_3 reduces the interaction between nickel and Al_2O_3 support,resulting in higher Ni reducibility and more Ni° active sites. With the increase of Mo O_3 content,the catalytic activity of Ni O-Mo O_3/ Al_2O_3 is firstly increased and then decreased. The catalyst with 3% of MoO_3 loading exhibits the best performance. Carbon deposition and sulfur poisoning are the two main factors of deactivation. The addition of appropriate amount of Mo O_3 to Ni/Al_2O_3 may increase the adsorption capacity of hydrogen and minimize the sulfur poisoning of Ni active sites,leading to better coking resistance and higher catalytic stability.
出处
《现代化工》
CAS
CSCD
北大核心
2016年第4期72-75,77,共5页
Modern Chemical Industry
关键词
甲烷化
镍
氧化钼
抗积碳
抗硫
methanation
nickel
molybdenum oxide
coke resistance
sulfur resistance
