Synthesis and catalysis of new metal sulfide cluster in shape-selective reaction space

本文用光谱方法研究了钴钼硫化物的性质和催化作用。结果表明，金属硫化物的催化作用是由原子簇的大小、原子价态和中心原子的配位决定的。采用多种方法对各因素进行单独控制是开发活性加氢处理催化剂的必要条件。本研究旨在为新型催化剂的设计提供依据，对硫化后的钴钼催化剂进行苯并噻吩加氢脱硫反应。在H_2S气氛中，协同效应得到了扩展。用NO探针观察了Co-Mo催化剂表面，发现催化剂表面的硫化物是由前驱体氧化物的硫化物转变而来的。通过对比经硫化-还原预处理的催化剂的活性，考察了硫化对催化剂加氢脱硫活性的影响。这些活性试验表明，预硫化虽然诱导了 ...更多信息 艾德催化剂的固有活性，即使在长时间的硫化后，预还原也会导致催化剂活性的劣化。对预硫化和/或预还原Co-Mo催化剂进行了光谱研究，发现预还原导致催化剂活性的降低与硫化钼的尺寸有关，并成功地将钼双簇引入到分子筛笼中，保持了Mo-Mo键。Mo/分子筛催化剂的活性低于常规Mo/Al_2O_3催化剂，且H_2S气氛对Mo/分子筛催化剂活性的劣化作用显著。在水溶液中用螯合剂制备了Co-Mo/Al_2O_3催化剂。结果表明，添加螯合物的催化剂的HDS活性高于市售Co-Mo/Al_2O_3催化剂，其中以钴、钼同时负载于Al_2O_3上的催化效果最为显著。有人认为，螯合剂有增加钴表面密度的作用，从而增加活性位点。少

We have studied the character and catalysis of cobalt/molybdenum sulfides by means of spectroscopic method. According to the results it is concluded that catalysis of metal sulfide is determined by cluster size, valence and coordination of the center atom. Individual control of each factor by various method is essential to develop the active hydrotreating catalyst. This study was performed to attain the basis for new catalyst design.Hydrodesulfurization (HDS) of benzothiophene was carried out over cobalt-molybdenum (Co-Mo) catalyst after sulfurization. The synergic effect was extended in hydrogen sulfide (H_2S) atmosphere. Co-Mo catalysts surface was observed by means of NO probe to fine that the synegy of the sulfides evolved from that of the precursor oxides. The effect of sulfiding on the catalyst HDS activity was investigated by comparing the activities of catalysts which were pretreated by sequential sulfiding and reducing. These activity tests showed that while presulfiding induc … More ed intrinsic activity of the catalyst, prereduction induced a deteriorating effect on the catalyst activity even after a prolonged sulfidation. Spectroscopic studies on the presulfided and/or prereduced Co-Mo catalyst were conducted and it was shown that the deteriorating of the catalyst activity induced by the prereduction was related to the size of molybdenum sulfide.Molybdenum dicluster was successfully introduced into zeolite cage maintaining the Mo-Mo bond. The activity of Mo/zeolite catalyst is lower than conventional Mo/Al_2O_3 catalyst and the deteriorating effect of H_2S atmosphere on the catalyst activity is remarkable on Mo/zeolite. There results imply that the size of molybdenum sulfide was limited in zeolitecage.Co-Mo/Al_2O_3 catalyst was prepared using chelating agent in an aqueous solution. The HDS activity of the chelate-added catalyst was higher than the commercially available Co-Mo/Al_2O_3 catalyst and the promoting effect was most remarkable when cobalt and molybdenum were simultaneously supported on Al_2O_3. It was suggested that the chelating agent has a role of increasing Co surface density ; thus, increasing the active site. Less