Liu Yi, Sheng Wei, Hou Zhanggui, Zhang Yi
State Key Laboratory of Organic-Inorganic Composites, Department of Chemical Engineering, Beijing University of Chemical Technology Beijing 100029 China
CNOOC Research Institute of Refining and Petrochemicals Beijing 102209 China
RSC Adv. 2018 Jan 9;8(4):2123-2131. doi: 10.1039/c7ra13147j. eCollection 2018 Jan 5.
The highly dispersed SiO-supported nickel-based catalysts for CO methanation were prepared by an ethylene glycol (EG) modified wet-impregnation method. The results indicate that the highly dispersed 20Ni/SiO (EG) catalyst realized good stability and higher catalytic activity than the catalyst obtained from a non-pretreated silica support (20Ni/SiO) in CO methanation, due to the smaller nickel particles and strong nickel-silica interaction. By the addition of a small amount of noble metal promoter (Ru, Pt, Pd), the catalytic activity for CO methanation was further improved dramatically and follows the order Ru > Pt > Pd. The added noble metal promoter enhanced the reduction of the nickel oxide by spill-over-hydrogen during reduction treatment, and provided more active species for the methanation reaction, resulting in 7 times higher CO conversion than the non-pretreated 20Ni/SiO catalyst. The 20Ni-0.5Ru/SiO (EG) catalyst presents superb catalytic performance in CO methanation with high activity (CO conv. 80.2%) as well as high methane selectivity (90.3%) at 275 °C without any deactivation during 50 h reaction. The obtained catalysts were characterized by XRD, TG/DTA, TEM, XPS, TPR, H chemisorption, and DRIFTS.
采用乙二醇（EG）改性的湿浸渍法制备了用于CO甲烷化的高度分散的SiO负载镍基催化剂。结果表明，高度分散的20Ni/SiO（EG）催化剂在CO甲烷化反应中表现出良好的稳定性，且催化活性高于由未预处理的二氧化硅载体（20Ni/SiO）制得的催化剂，这归因于其镍颗粒较小以及镍-二氧化硅相互作用较强。通过添加少量贵金属促进剂（Ru、Pt、Pd），CO甲烷化的催化活性得到进一步显著提高，且活性顺序为Ru > Pt > Pd。添加的贵金属促进剂在还原处理过程中通过溢流氢增强了氧化镍的还原，并为甲烷化反应提供了更多活性物种，使得CO转化率比未预处理的20Ni/SiO催化剂高7倍。20Ni-0.5Ru/SiO（EG）催化剂在CO甲烷化反应中表现出优异的催化性能，在275℃下具有高活性（CO转化率80.2%）以及高甲烷选择性（90.3%），在50小时反应过程中无任何失活现象。采用XRD、TG/DTA、TEM、XPS、TPR、H化学吸附和DRIFTS对所得催化剂进行了表征。
