Preparation of various transition metal coordination polymer complexes and their catalytic behavior as nanospace catalysts

我们研究了Rh（二羧酸）、Co（联吡啶）和金属包封二氧化硅和二氧化钛纳米管催化剂在配位聚合物上的催化行为和吸附行为。当用富马酸、象皮酸、萘二羧酸、mucone酸作为配体时，Rh二羧酸配合物表现出h2、CO、NO、各种烯烃和pallafines（每个Rh金属有几个分子）的气体遮挡能力。遮挡量取决于配体和吸收分子的大小，但聚合物配合物的逐渐结晶导致遮挡量的减少。h_2 - d2在200 K的低温下发生了氢交换反应，并且在解离吸附的H(a)和D(a)之间以及D(a)与配体分子中的氢之间观察到两种不同的交换机制。在室温下，烯烃的氢交换和氢化也发生了，前者的交换只在聚合物配合物的孔内进行，而后者的交换既在孔内进行，也在配合物的外表面进行。随着催化反应的不断重复，配合物再次逐渐结晶。透射电镜观察显示均匀的球形颗粒，而不是片状结构。Co（联吡啶基）配位聚合物配合物中存在大量的NH_3遮挡，加速了NH_3对NO的还原，表明孔结构对NO-NH_3反应形成N_2选择性起重要作用。Pt-SiO_2纳米管的高温抽吸使H_2的选择性渗透逐渐发生，表明在硅壁网络内形成了超微孔隙。管内存在少量10 nm的Pt颗粒，壁面硅网中存在亚nm的Pt团簇，后者可能是CO-H_2反应特征性催化行为的原因。Pt包埋TiO_2纳米管在CO-H_2O和CO-H_2反应中的TOF比传统浸渍Pt/TiO_2催化剂高一个数量级。在纳米管催化剂的情况下，CO-H_2反应生成甲醇的选择性达到90%以上。傅里叶变换红外光谱（FT-IR）观察到，纳米管催化剂具有异常强的CO吸附作用，这可能是这些纳米管催化剂具有这些独特催化行为的原因。少

We have investigated the catalytic behavior as well as adsorption behavior over coordination polymer complexes of Rh(dicarboxilate), Co(bipyridyl) and metal encapsulated silica and titania nanotube catalysts.When fumalic acid, thelephalic acid, nathalene dicarboxylic acid, mucone acid were used as ligands, Rh dicroboxylic complexes exhibited gas occlusion ability such as H_2, CO, NO, various olefins and pallafines (several molecules per one Rh metal). The amount of occlusion depended on the sizes of ligands as well as absorbent molecules, however, gradual crystallization of the polymer complexes took place, which caused the decrease of the amount of occlusion. H_2-D_2 hydrogen exchange reaction took place as low temperatures as 200 K, and two different exchange mechanisms were observed between dissociatively adsorbed H(a) and D(a) and between D(a) and hydrogen in ligand molecules. Hydrogen exchange and hydrogenation of olefin also took place below room temperatures, where former exchan … More ge proceeded only inside the pores of the polymer complexes although the latter exchange proceeded both inside the pores and over outer surfaces of the complexes. The gradual crystallization of the complexes again took place with the repeated catalytic reactions. TEM observation revealed uniform sphere particles rather than sheet structures.In the case of Co(bipyridyl) coordination polymer complexes, a large amount of NH_3 occlusion was observed, which accelerated the reduction of NO by NH_3, showing a important role of pore structures for NO-NH_3 reaction to form N_2 selectivery.Selective permeation property of H_2 took place progressively by higher temperature evacuation of Pt-SiO_2 nanotubes, indicating the formation ultra micro pores inside the network of silica walls. There existed a few ten nm Pt particles inside the tubes and sub-nm Pt clusters inside the silica networks of the wall, and the latter Pt might be responsible for the characteristic catalytic behavior in CO-H_2 reaction. Pt encapsulated TiO_2 nanotubes exhibited one order of magnitude larger TOF in CO-H_2O and CO-H_2 reactions than conventional impregnated Pt/TiO_2 catalysts. More than 90% selectivity for methanol formation was acheved in CO-H_2 reaction in the case of nanotube catalysts. Exceptionally strongly adsorbed CO, which was observed by FT-IR may be responsible for these unique catalytic behavior of these nanotube catalysts. Less