A Study on the Characterization of Hydrodesulfurization Catalysts by Magnetic Properties of Co toward the Development of Highly Active Catalysts

本研究项目的显著发现如下：1。Co- mo - s相中的Co硫化物表现出反铁磁行为。用理论方程模拟了Co原子的磁化率，假设形成Co- s -Co键的Co调光团簇，与NO吸附一致，表明最大NO吸附量为NO/Co = 1/1摩尔比。本文提出的Co-Mo-S结构得到了CVD-Co/MoS_2催化剂XAFS分析的支持。研究了在Co-Mo/Al_2O_3中加入硼以提高其加氢脱硫活性。结果表明，硼的加入使TOF提高了1.6倍，表明发生了ace反应，从而导致Mo氧化物与Al_2O_3表面的相互作用减弱。硼的加入降低了二硫化钼的分散性，这是由于二硫化钼粒子的分散性受到影响。高温硫化提高了Co-Mo-S结构的固有活性，而mo - s结构由于Mo-O-Al键强而活性较低。而硼的加入降低了II型的硫化温度。硼的加入降低了Co-Mo-S相的热稳定性。以Co(Co)_3NO为前驱体，在沸石孔隙中成功制备了高度分散的Co硫化团簇。其结构取决于载体沸石的类型。研究发现，Co硫簇与沸石质子反应生成Co2+阳离子，释放出H_2S。Co_sulfide团簇的加氢脱硫活性取决于其结构和剩余OH基团。提出通过修饰MoS_2颗粒与载体表面的相互作用，合成高度分散的Co-Mo-S型，制备高活性加氢处理催化剂。硼和螯合剂的同时使用对开发高活性超深层加氢脱硫催化剂是非常有效的。

The salient findings in this research project are as follows:1. The Co sulfide species in the Co-Mo-S phase show an antiferromagnetic behavior. The magnetic susceptibility of the Co atoms was simulated by a theoretical equation assuming the formation of Co dimmer clusters with Co-S-Co bonding, in conformity with the NO adsorption, which shows the maximum NO adsorption capacity is NO/Co = 1/1 molar ratio. The proposed Co-Mo-S structure was supported by our recent XAFS analysis of CVD-Co/MoS_2 catalysts.2. The addition of boron to Co-Mo/Al_2O_3 was studied to improve the hydrodesulfurization activity. It was found that the addition of boron increases the TOF by 1.6 times, indicating the ace reactions, accordingly resulting in weaker interactions between Mo oxides and Al_2O_3 surface. The dispersion of MoS_2 was decreased by the addition of boron because of ence in the dispersion of MoS2 particles.3. The intrinsic activity of the Co-Mo-S structure was increased by sulfiding at a high temperatur-Mo-S structure showed a much less activity because of strong Mo-O-Al bonding. However, the addition of boron decreased the sulfidation temperature for the formation of Type II. The thermal stability of the Co-Mo-S phase was decreased by the addition of boron.4. Highly dispersed Co sulfide clusters were successfully prepared in zeolite pores using Co(CO)_3NO as a precursor. The structure depended on the type of the host zeolite. It was found that Co sulfide clusters react with zeolite protons to form Co2+ cations liberating H_2S. The hydrodesulfurization activity of the Co_sulfide clusters depended on the structure and residual OH groups.5. It is proposed that highly active hydrotreating catalysts are prepared by synthesizing highly dispersed Co-Mo-S Type II by modifying the interactions between MoS_2 particles and support surface. Simultaneous use of boron and chelating agents will be very effective for the developments of highly active ultra-deep hydrodesulfurization catalysts.