Mo—Ni／Al2O3催化剂的TPR特性与加氢脱硫性能

应用ＴＲＰ、ＸＰＳ及ＸＲＤ等技术研究了用浸渍法制备了的Ｎｉ／Ａｌ２Ｏ３、Ｍｏ／Ａｌ２Ｏ３和Ｍｏ－Ｎｉ／Ａｌ２Ｏ３３种催化剂的还原性能，并将Ｍｏ－Ｎｉ／Ａｌ２Ｏ３双金属催化剂与同类型的Ｍｏ－Ｃｏ／Ａｌ２Ｏ３和Ｗ－Ｎｉ／Ａｌ２Ｏ３催化剂进行了比较。结果表明：在Ｍｏ－Ｎｉ－Ａｌ２Ｏ３中，ＭｏＯ３呈高度分散状态，ＮｉＯ的加入减弱了Ｍｏ与载体间的强相互作用，并在催化剂表面形成了两种易还原的复合物，大大降低了     

钙钛矿型稀土复合氧化物超细粒子对CO还原SO2的催化性能

以共沉淀－－超临界干燥法制钙钛矿型ＬａＣｏＯ３和ＬａＭｎＯ３稀土合氧化物超细粒子,测试了该超细粒子对ＣＯ还原Ｓ煌催化性能,发现随ＬａｃｏＯ３和ＬａＭｎＯ３颗粒粒径减小和比表面积增大其对ＣＯ还原Ｓ煌催化活性提高。反应产物证棂单质硫,有微量ＣＯＳ和ＣＳ２生成,其中ＣＯＳ可能是ＣＯ还原ＳＯ２生成单质硫过程中的中间产物。     

Co－Mo－K／Al_2O_3系耐硫变换催化剂硫化过程的研究

以工厂实用的加有ＣＳ２的半水煤气为硫化气源，采用ＴＧ、ＤＴＡ、ＳＥＭ、ＥＤＳ、ＸＲＤ等表征技术，对Ｃｏ－Ｍｏ－Ｋ／Ａｌ２Ｏ３系耐硫变换催化剂的各个组份及其组合试样进行了恒温硫化及程序升温硫化实验研究。全面考察了温度对硫化过程的影响．比较了不同活性组份的硫化行为，探讨了各组份在硫化过程中的作用。     

新型Co-Mo/TiO_2加氢转化催化剂不预硫化过程的研究

讨论了新型Ｃｏ┐Ｍｏ／ＴｉＯ２加氢转化催化剂的反应机理和影响反应的诸因素，结果表明，新型催化剂与传统Ｃｏ┐Ｍｏ／Ａｌ２Ｏ３加氢转化催化剂相比具有不预硫化和高初活性的特点     

用31P-NMR谱法分析硫化二硫代磷酸钼摩擦改进剂的组分

报道了关于＾３１Ｐ－ＮＭＲ谱法分析不同反应条件下所制得硫化二硫代磷酸钙摩改进剂的组分及其变化。结果表明,所合成８种Ｓ－ＭｏＤＴＰ产物均是由１２－１３个有机５价Ｍｏ－Ｓ、Ｐ＝Ｓ、Ｐ＝Ｏ化合物及有机３价Ｐ－Ｓ化合物组成的混合物,其中随着反应温度从３０℃升至１００℃,     

新型（不预硫化）Mo—Co／TiO2加氢转化催化剂的反应机理,制备和性能评价

阐述新型（不预硫化）Ｍｏ－Ｃｏ／ＴｉＯ２加氢转化硫（ＨＤＳ）催化剂的反应机理和制备方法；新催化剂具有不需预硫化过程，且初活性及稳定性均高等优点。     

气相法合成2—乙基—3,5—二甲基吡啶的研究

介绍了催化剂的制备方法,用微型反应色谱系统在常压,３５０℃,原料物质的量配比为ＮＨ３：Ｃ３Ｈ６Ｏ＝１：２的条件下,考察了各种催化剂对２－乙基－３,５－二甲基吡啶（ＥＤＭＰ）收率的影响,催化剂为Ｃｏ３Ａｌ２（ＰＯ４）４时,ＥＤＭＰ的收率最高;考察了催化剂粒度圣转化率的影响,粒径小于０．８ｍｍ时转化率较高,研究了温度对ＥＤＭＰ收率的影响,确定合适温度为３５０～４００℃。     

利用A1—Co—Mo催化剂废渣研制生产钴系陶瓷颜料

采用煅烧和碱洗的方法试制成功了Ａ１－Ｃｏ－Ｍｏ催化剂废渣的预处理工艺,并着重探讨了用该工艺处理后的Ａ１－Ｃｏ－Ｍｏ废渣取代部分Ｃｏ２Ｏ３生产钴系陶瓷颜料。     

在Mo－Sb－O复合氧化物催化剂上甲醇的氧化酯化反应

研究了在Ｍｏ－Ｓｂ－Ｏ复合氧化物催化剂上甲醇的氧化酯化反应，讨论了工艺条件对甲醇转化率和甲酸甲酯选择性的影响，考察了Ｍｏ－Ｓｂ－Ｏ复合氧化物催化剂的性能。     

不同杂质对Co—Mo系耐硫变换催化剂性能的影响

本文介绍了不同杂质对ＣｏＯ－ＭｏＯ３系耐硫变换催化剂性能的影响。     

The evolution of the active phase in CoMo/C hydrodesulfurization catalysts under industrial conditions: a high-pressure Mössbauer emission spectroscopy study

Mössbauer emission spectroscopy (MES) was used to study the influence of high pressure on the sulfidation of CoMo/C catalysts. During temperature stepwise treatment at 4 MPa the catalysts' behavior closely follows the Co–Mo–S model. The obtained MES spectra are different from those previously observed for CoMo/C catalysts sulfided under atmospheric pressure conditions, where the highly dispersed Co₉S₈-type structures are formed. It is suggested that the high-pressure conditions induce the binding of Co and Mo intermediate species, favoring Co–Mo–S phase formation. The results indicate that the contradictions between some catalyst models are partly related to the formation of different Co species upon different activation procedures. Lower stability compared with the alumina-supported catalysts was observed for the Co sulfide species in the CoMo/C catalysts under high-pressure sulfiding conditions. This can have important implications for the high-pressure stability of Type II Co–Mo–S, which is believed to have the same properties as the carbon-supported Co–Mo–S structures.     

有机硫加氢(HDS)催化剂的预硫化

预硫化是HDS、HDN过程中决定催化剂活性的最重要环节。在分析催化剂硫化反应原理、硫化条件、硫化与还原的关系等基础上进一步指出了在工业过程中预硫化的一些原则。     

States of carbon nanotube supported Mo-based HDS catalysts

As HDS catalysts, the supported catalysts including oxide state Mo, Co–Mo and sulfide state Mo on carbon nanotube (CNT) were prepared, while the corresponding supported catalysts on γ-Al₂O₃ were prepared as comparison. Firstly, the dispersion of the active phase and loading capacity of Mo species on CNT was studied by XRD and the reducibility properties of Co–Mo catalysts in oxide state over CNTs were investigated by TPR while the sulfide Co–Mo/CNT catalysts were characterized by XRD and LRS techniques. Secondly, the activity and selectivity of hydrodesulfurization (HDS) of dibenzothiophene with Co–Mo/CNT and Co–Mo/γ-Al₂O₃ were studied. It has been found that the main active molybdenum species in the oxide state MoO₃/CNT catalysts were MoO₂, rather than MoO₃ as generally expected. The maximum loading before formation of the bulk phase was lower than 6%m (calculated in MoO₃). The TPR studies revealed that that active species in oxide state Co–Mo/CNT catalysts were more easily reduced at relatively lower temperatures in comparison to those in Co–Mo/γ-Al₂O₃, indicating that the CNT support promoted the reduction of active species. Among 0–1.0 Co/Mo atomic ratio on Co–Mo/CNT, 0.7 has the highest reducibility. It shows that the Co/Mo atomic ratio has a great effect on the reducibility of active species on CNT and their HDS activities and that the incorporation of cobalt improved the dispersion of molybdenum species on CNT and mobilization. It was also found that re-dispersion could occur during the sulfiding process, resulting in low valence state Mo₃S₄ and Co–MoS_2.17 active phases. The HDS of DBT showed that Co–Mo/CNT catalysts were more active than Co–Mo/γ-Al₂O₃ and the hydrogenolysis/hydrogenation selectivity of Co–Mo/CNT catalyst was also much higher than Co–Mo/γ-Al₂O₃. For the Co–Mo/CNT catalysis system, the catalyst with Co/Mo atomic ratio of 0.7 showed the highest activity, whereas, the catalyst with Co/Mo atomic ratio of 0.35 was of the highest selectivity.     

负载型钴铜双金属氮化物催化氨分解研究

Co and Mo bimetallic nitrides supported on Mg（Al）O, MgO and γ-Al2O3 were prepared in temperatureprogrammed reactions with NH3. The surface morphology, chemical composition and catalytic activity for NH3 decomposition on the supported Co and Mo bimetallic nitrides were studied by X-ray diffractometer （XRD）, NH3 temperature-programmed desorption and mass spectrometer （NH3-TPD-MS）, temperature-programmed desorption and mass spectrometer （TPD-MS）, H2 temperature-programmed surface reaction （H2-TPSR） and activity test. The phases of Co3Mo3N and MoN could be formed on Mg（Al）O, MgO and Al2O3 during the nitridation, and they might be more uniformly dispersed on Mg（Al）O and MgO than on γ-Al2O3. Transition metallic nitrides are generally considered as potential catalysts for hydrogen-involving reactions due to the entrance of hydrogen atoms into subsurface and the lattice of metallic nitrides. The diffusion of nitrogen in the bulk and the structure transformation of Co and Mo nitride compounds occur during NH3-TPD, but the supported Co and Mo bimetallic nitrides are not easily reduced at H2 atmosphere. Co3Mo3N/Mg（Al）O catalyst exhibits the highest activity, while Co3Mo3N/Al2O3 exhibits the lowest activity for NH3 decomposition. Furthermore, the catalytic activity of Co and Mo bimetallic nitrides is not only much higher than that of supported single metallic nitride, but also highly dependent upon the surface acidity and BET surface area of support.     

Kinetic study of carbon nanotube synthesis over Mo/Co/MgO catalysts

The kinetics of carbon nanotube (CNT) synthesis by decomposition of CH₄ over Mo/Co/MgO and Co/MgO catalysts was studied to clarify the role of catalyst component. In the absence of the Mo component, Co/MgO catalysts are active in the synthesis of thick CNT (outer diameter of 7-27 nm) at lower reaction temperatures, 823-923 K, but no CNTs of thin outer diameter are produced. Co/MgO catalysts are significantly deactivated by carbon deposition at temperatures above 923 K. For Mo-including catalysts (Mo/Co/MgO), thin CNT (2-5 walls) formation starts at above 1000 K without deactivation. The significant effects of the addition of Mo are ascribed to the reduction in catalytic activity for dissociation of CH₄, as well as to the formation of Mo₂C during CNT synthesis at high temperatures. On both Co/MgO and Mo/Co/MgO catalysts, the rate of CNT synthesis is proportional to the CH₄ pressure, indicating that the dissociation of CH₄ is the rate-determining step for a catalyst working without deactivation. The deactivation of catalysts by carbon deposition takes place kinetically when the formation rate of the graphene network is smaller than the carbon deposition rate by decomposition of CH₄.     

Investigation of the sulfidation of Mo/TiO2-Al2O3 catalysts by TPS and LRS

A series of Mo/Al₂O₃ and Mo/TiO₂-Al₂O₃ catalysts were investigated by temperature programmed sulfiding (TPS) and laser Raman spectroscopy (LRS). The effect of TiO₂ on the sulfidability of molybdena was studied in detail. It is found that Mo/Al₂O₃ catalysts can be partially sulfided by O-S exchange at low temperature, forming molybdenum oxysulfide. The Mo-S bond subsequently ruptures in the presence of H₂ to produce H₂S. At 530–550 K deep sulfiding of molybdenum oxysulfide occurs forming crystalline MoS₂. When the surface of Al₂O₃ was covered by a monolayer of TiO₂, the sulfiding rate of molybdena at low temperature was not only greatly increased, but H₂S produced in the reduction of Mo-S species caused deep sulfiding of the catalyst which resulted in a decrease of the TPS peak temperature by 80–100 K. The results indicate that this promotion of the sulfiding of molybdena is enhanced with TiO₂ loading. The function of TiO₂ is explained by the weakened interaction between MoO₃ and Al₂O₃ due to the coverage of the Al₂O₃ surface by TiO₂.     

一种体相加氢脱硫催化剂的程序升温硫化表征

在全自动化学吸附仪上,用程序升温硫化（TPS）技术对一种体相加氢脱硫催化剂进行表征,考察了金属与载体的相互作用、金属间的相互作用以及焙烧温度对这种催化剂硫化性能的影响。结果表明,MoO3负载于Al2O3载体后,硫化峰温大幅降低,并在TPS谱图中体现出分步硫化的过程,证明MoO3与载体间存在相互作用,形成了易于硫化还原的活性中心。当Mo和Ni共同作用于载体时,形成了更易于硫化的Mo-Ni-O复合相。Co的加入加强了Mo与Ni间的协同作用,Co、Mo、Ni与Al形成了更易硫化的活性中心。W的加入反而改变了硫化中心的性质,使硫化温度提高。对（Mo＋Ni）/Al2O3和（Co＋Mo＋Ni）/Al2O3催化剂,于500℃焙烧时,催化剂硫化性能最好。最后得出结论：当Co、Mo、Ni 3种金属共同作用于载体,并于500℃焙烧时,其硫化中心活性最高。     

Highly active sulfided CoMo catalyst on nano-structured TiO2

High surface area (>300 m² g⁻¹) nano-structured TiO₂ oxides (ns-T) were used as CoMo hydrodesulfurization catalyst support. Cylindrical extrudates were impregnated by incipient wetness with Mo (2.8 Mo at. nm⁻²) and Co (atomic ratio Co/(Co + Mo) = 0.3). Characterization of impregnated precursors was carried out by N₂ physisorption, XRD and atomic absorption and laser-Raman spectroscopies. Sulfided catalysts (400 °C, H₂S/H₂) were studied by X-ray photoelectronic spectroscopy. As indicated by XRD and after various preparation steps (extrusion, Mo and Co impregnation and sulfiding) the nano-structured material was well preserved. XPS analyses showed that Co and Mo dispersion over the ns-T support was much higher than that on alumina. Very high surface S concentration suggested that even ns-T was partially sulfided during catalyst activation. Dibenzothiophene hydrodesulfurization activity (5.73 MPa, 320 °C, n-hexadecane as solvent) of CoMo/ns-T was two-fold to that of an alumina-supported commercial CoMo catalyst. The improvement was even more remarkable in intrinsic pseudo kinetic constant basis. No important differences in selectivity over the catalysts supported on either Al₂O₃ or ns-T were observed, where direct desulfurization to biphenyl was favored. Both Mo dispersion and sulfidability were enhanced on the ns-T support where Mo⁴⁺ fraction was notably increased (100%) as to that found on CoMo/Al₂O₃.     

Novel Mo/Ga/H-ZSM-5 catalyst in environmentally important reductive transformation of N2O in presence of CH4

Direct decomposition of N₂O and the reduction of N₂O with CH₄ over Ga/H-ZSM-5 and Mo/Ga/H-ZSM-5 (Si/Al = 40) catalysts in a plug flow reactor under steady-state conditions as well as by temperature programmed surface reaction (TPSR) have been investigated. Ga ions were ion-exchanged from liquid phase while Mo was deposited onto the Ga/H-ZSM-5 sample using incipient wetness technique. The catalysts were characterized by means of XRF, XPS, TPR, CO chemisorption, TEM and EDS. The N₂O forms redox centers in the Mo/Ga/H-ZSM-5 catalysts at elevated temperatures, which are extremely active in the reaction with CH₄ already at around 373 K. Addition of Mo to the Ga/H-ZSM-5 decreased the T₅₀ temperature in the N₂O decomposition and reduction of N₂O with CH₄ from 819 to 787 K and from 755 to 646 K, respectively. The oxidation/reduction of the Mo/Ga/H-ZSM-5 sample is more favoured in the interaction with N₂O/CH₄ as compared to that using O₂/H₂ and the mechanism of the redox reactions might also be different. The reduction of N₂O with CH₄ cannot be described with the Mars–van Krevelen redox mechanism, but by the participation of CH₄ via MoGa–OCH₃ species in a complex oxygen transfer mechanism is proposed at which N₂O does not directly reoxidise the reduced active centers.     

Effect of the activation process on thiophene hydrodesulfurization activity of activated carbon-supported bimetallic carbides

The effect of passivation and presulfidation after carbiding of activated carbon-supported Fe–Mo, Co–Mo and Ni–Mo catalysts on their thiophene HDS activity was evaluated. Catalytic precursors were prepared by co-impregnation of the support with solutions of ammonium heptamolybdate and the promotor nitrates or sulfates. Carbiding was achieved by means of the carbothermal method, employing pure H₂ as reductant and the support as the carbon source. Carbided samples were submitted to one out of three types of procedures before HDS tests: (a) passivation at room temperature followed by presulfiding; (b) presulfiding (no passivation); and (c) neither passivation nor sulfiding before HDS. Samples of passivated catalysts prepared from the sulfates of Fe, Co or Ni contained variable amounts of sulfur, as shown by XPS and elemental analysis, while XRD showed only metals and mixed Fe₃Mo₃C or η-M₆Mo₆C₂ (MCo, or Ni) phases. The nitrate-derived catalysts only presented β-Mo₂C and metals (XRD). Sulfur containing catalysts showed high initial activities although deactivate strongly during the first 40 min on the reaction stream, while the unsulfided nitrate-derived samples showed a more stable behavior and lower activities during the 2–3 h of testing. In general, samples submitted to passivation followed by presulfiding showed the higher steady state activities and those neither passivated nor sulfided were the less active. The results show the benefits of a passivating treatment on these carbon-supported catalysts, and point out to the importance of sulfided surface phases in HDS on carbides of transition metal catalysts.