Synthesis of complex metal cluster and creation of new synergy

为了在分子水平上揭示协同作用的原因，尝试使用由螯合剂、金属络合物和金属离子合成的络合金属簇来创建新的协同作用。研究了氨三乙酸（NTA）对Co-Mo/Al_2O_3催化剂加氢脱硫活性的促进作用。以NTA为螯合剂，采用浸渍法制备Co-Mo/Al_2O_3催化剂，提高了协同位（活性位）的选择性合成。本研究发现EDTA和反式-1，2-环己二胺-N，N，N^1，N^1-四乙酸（CyDTA）具有较高的促进作用。Cy-DTA-Co-Mo/Al_2O_3催化剂的HDS活性比Co-Mo/Al_2O_3催化剂提高了70%。为了探讨催化剂的活性促进机理，通过红外光谱研究了NO在沸石分子筛笼上的吸附行为。 ...更多信息 启动子和Mo位点。为了进一步研究活性中心的局域结构，还测量了Mo的K边EXAFS。虽然每个CUS的HDS活性增加，但螯合剂的效果在被推测为在反应条件下支持活性位点的MoS 2簇的分散性和配位不饱和位点（CUS）的数量方面变化很大。结果表明，钴的高度分散是形成活性中心的必要条件。比较了Ni-Mo/Al_2O_3和Ni-W/Al_2O_3与Co-Mo/Al_2O_3的HDS活性。而在Ni-Mo/Al_2O_3催化剂中，NTA和CyDTA的加入对催化剂的HDS活性没有影响，Cy-DTA-Ni-W/Al_2O_3催化剂的HDS活性比Ni-W/Al_2O_3催化剂提高了60%。结果表明，金属离子的结合是影响螯合剂促进效果的重要因素之一。少

For the purpose of uncovering the cause of synergy at molecular level, creation of new synergy was attempted using a complex metal cluster synthesized from chelating agent, metal complex and metal ion. We found the promoting effect of nitrilotriacetic acid (NTA)on hydrodesulfrization (HDS) activity of cobalt-molybdenum/alumina (Co-Mo/Al_2O_3) catalyst. Selective synthesis of synergistic site (active site) was enhanced when Co-Mo/Al_2O_3 catalysts were prepared by an impregnation method using NTA as chelating agent. In this study it was found that EDTA and trans-1,2-cyclohexane diamine-N,N,N^1, N^1-tetra-acetic acid (CyDTA) shows higher promoting effect. HDS activity of Cy-DTA-Co-Mo/Al_2O_3 was 70% higher than that of Co-Mo/Al_2O_3. Incorporation of these chelated complex into zeolite cage nor synthesis of complex chelate cluster in the cage was not confirmed.In order to inverstigate the mechanism of activity promotion, IR spectra were measured to examine the behavior of adsorbed NO on … More the promoter and Mo sites. Mo K-edge EXAFS was also measured for clarify the local structure of active site. While HDS activity per CUS was increased, the effect of chelating agent vary greatly in dispersion of MoS2 cluster which is presumed to support the active site under reaction conditions, and in the number of coordinatively unsaturated site (CUS). It was suggested that highly dispersed cobalt is essential for formation of active site. Thus, it was demonstrated that dispersion of coblat is enhanced by chelating agent without changing local structure of active site.HDS activity of nickel-molybdenum/alumina (Ni-Mo/Al_2O_3) and nickel-tungsten/alumina (Ni-W/Al_2O_3) was compared with that of Co-Mo/Al_2O_3. While in the case of Ni-Mo/Al_2O_3, HDS activity was not influenced by NTA nor CyDTA addition, that of Cy-DTA-Ni-W/Al_2O_3 was 60% higher than that of Ni-W/Al_2O_3. The result shows that combination of metal ion is one of an important factor for the promotion effect of chelating agent. Less