Co_2Si@C催化剂的合成及其加氢脱硫性能

采用微波法制备了Co_2Si@C催化剂并对其在加氢脱硫反应中的催化性能进行了研究.通过XRD、 XPS、 TEM和N_2-物理吸附表征分析Co_2Si@C催化剂的组成和结构. Co_2Si@C催化剂具有一致的介孔结构,高钴含量(21%)、高比表面积(116.6 m~2·g~(-1))和均匀分布的纳米粒子.由于硅原子对钴原子结构和参数的修饰、纳米粒子效应和高金属含量等因素, Co_2Si@C催化剂在温和的反应条件下(340℃和3.0 MPa)具有良好的加氢脱硫活性和对直接脱硫(DDS)反应途径的高选择性,产物联苯的选择性超过了60%.     

Synthesis and conversion of alcohols over modified transition metal sulphides

Alkali modified (Co/Ni)MoS systems are promising catalysts for higher alcohol synthesis from synthesis gas. The influence of various supports, modifiers and promoters on the activity of sulphide catalysts is reviewed. It is found that alkali metal reduces support acidity and affects the active phase morphology and active site functioning. Promotion of the catalyst with Co and Ni favours alcohol formation. KCoMoS catalyst activity in syngas conversion and hydrodesulphurization reactions is studied. An effect of organic compound additives such as methanol, ethanol, and ethylene on the catalyst behaviour is studied. It is suggested that alcohol formation may proceed in two steps: CO insertion and aldol condensation. Which of the two dominates depends on the reaction conditions.     

Synthesis and characterization of vanadium nanoparticles on activated carbon and their catalytic activity in thiophene hydrodesulphurization

Vanadium nanoparticles (∼7 nm) stabilized on activated carbon were synthesized by the reduction of VCl₃·3THF with K[BEt₃H]. This material was characterized by inductive coupled plasma-atomic emission spectroscopy (ICP-AES), high-resolution transmission electron microscopy (HRTEM) and X-ray photoelectron spectroscopy (XPS) analyses. The catalytic performance of the carbon-supported vanadium was studied using thiophene hydrodesulfurization (HDS) as model reaction at 300 °C and P = 1 atm. The catalytic activity of the vanadium carbide phase on the activated carbon carrier was more significant than that of the reference catalysts, alumina supported NiMoS. The method proposed for the synthesis of such a catalyst led to an excellent performance of the HDS process.     

TiO2-Al2O3复合氧化物负载NiMo加氢脱硫催化剂的研究

采用溶胶凝胶技术，从Al2O3载体的表面改性出发，制备了TiO2-Al2O3复合载体。采用此改性载体制备了NiMo／TiO2-Al2O3催化剂；用中压固定床微反装置考察了载体改性对制备的催化剂的噻吩加氢脱硫(HDS)活性的影响．用透射电镜、NH3-TPD及吡啶红外光谱法对改性载体和催化剂进行了表征．结果表明，经钛溶胶改性的载体制备的催化剂与原有载体制备的催化剂相比，催化剂活性提高了20％．改性载体表面负载的钛溶胶以纳米尺寸的TiO2微粒形态存在．     

Mo-Ni-γ-Al2O3体系中Mo、Ni近邻结构的EXAFS研究

运用EXAFS技术对加入P2O5或TiO2的MO-Ni-γ-Al2O3体系中Mo、Ni的K吸收边进行了分析，获得了体系中金属组分原子周围的微观结构信息，从而进一步证实P或Ti的加入有助于含量较高的Mo、Ni在载体表面的高度分散，样品中适量的P有助于形成较多的八面体结构，所有含P的样品中八面体结构含量均高于含Ti的样品，八面体结构Mo-O键上的氧在加氢脱硫反应中较易被硫取代，因而提高反应活性，这是含八面体结构较多的MoNiP样品的加氢脱硫活性优于MoNiTi样品的一个重要原因.     

A study of Co/Mo/Al2O3 hydrodesulphurization catalysts and related model compounds byxps and x-ray absorption spectroscopy (xanes andexafs )

A detailed investigation of sulphided Co/Mo/Al₂O₃ catalysts, their oxide precursors and several model oxides and sulphides of cobalt and molybdenum has been carried out using x-ray photoelectron spectroscopy and x-ray absorption spectroscopy (xanes andexafs). Octahedrally coordinated Co(II) and Mo(IV) are shown to be present in a sulphidic environment on the surfaces of these catalysts. The surface species contain an excess of sulphur, probably involving disulphide linkages. The surface compositions of the catalysts examined conform to the general formula Co¹¹ Mo _2n ^IV (2n + 3)S ₂ ²⁻ (2n -2)S²⁻.