CO_2催化加氢甲烷化研究进展

介绍了CO2加氢甲烷化反应及其热力学性质。从催化剂和反应机理等角度阐述了CO2加氢甲烷化反应研究进展。认为采取全球CO2循环策略系统是降低大气中CO2含量的一条有效途径。

Ni-Mn催化剂结构的EXAFS研究

本文用EXAFS方法测定了CO_2加氢甲烷化的镍锰双金属催化剂的结构。Ni-Mn/SiO,催化剂中镍和锰的EXAFS谱采用透射法获得,实验数据经过快速付立叶变换及最小二乘法参数拟合处理后.焙烧的Ni-Mn/SiO_2(Ox)催化剂的R_(Ni-O)=2.05A,R_(Mn-O)=1.90A,Ni和Mn的RSFs图分别与NiO、MnO_2的相近,表明镍、锰主要是以NiO、MnO_2的晶粒分散在SiO_2载体上.还原的Ni-Mn/SiO_2(Re)催化剂的R_(Ni-Ni)=2.50A,R_(Mn-O)=2.27A,说明已经生成了金属镍和MnO,镍的配位数为7.3,表明Ni-Mn/SiO_2(Re)中镍是以高分散的小晶粒存在。XRD方法也只观察到Ni-Mn/SiO_2(Re)有很弱的衍射峰,也证实生成的Ni、MnO晶粒是很小的,与EXAFS有一致的结论。与Ni/SiO_2催化剂相比,Ni-Mn/SiO_2(Re)催化荆的CO_2甲烷化高活性原因,我们认为是Ni与MnO的强相互作用及镍的高分散导致的。

Advances in the studies of the supported ruthenium catalysts for CO_(2) methanation

CO_(2) methanation has a potential in the large-scale utilization of carbon dioxide.It has also been considered to be useful for the renewable energy storage.The commercial pipeline for natural gas transportation can be directly applied for the methane product of CO_(2) methanation.The supported ruthenium(Ru)catalyst has been confirmed to be active and stable for CO_(2) methanation with its high ability in the dissociation of hydrogen and the strong binding of carbon monoxide.CO_(2) methanation over the supported Ru catalyst is structure sensitive.The size of the Ru catalyst and the support have significant effects on the activity and the mechanism.A significant challenge re-mained is the structural controllable preparation of the supported Ru catalyst toward a sufficiently high low-temperature activity.In this review,the recent progresses in the investigations of the supported Ru catalysts for CO_(2) methanation are summarized.The challenges and the future devel-opments are also discussed.