FCC过程中镁铝尖晶石对硫化物的吸附作用

通过比较改性镁铝尖晶石与FCC催化剂在不同装填方式时产品汽油中的硫含量,考察改性镁铝尖晶石对不同烃油馏分硫化物的吸附性能。结合物化表征,探讨催化裂化过程中改性镁铝尖晶石对烃油中硫化物的吸附作用。结果表明,镁铝尖晶石经过渡金属改性后,弱酸比例提高,中孔分布集中,可增强尖晶石对硫化物尤其是较大分子硫化物的吸附能力,吸附原料油和裂化产物中的硫化物,将其转化成焦炭或焦炭前驱物沉积于尖晶石表面,是改性尖晶石降低汽油产物硫含量的重要途径之一。镁铝尖晶石中引入适当的过渡金属,可以实现降低催化裂化汽油硫含量的目标。     

镁铝双金属醇盐合成工艺的研究

介绍了镁铝双金属醇盐的合成方法,详细介绍和评述了乙醇镁铝、异丙醇镁铝、正丁醇镁铝、异丁醇镬铝等双金属醇盐的合成工艺。正丁醇镁铝、异丁醇镁铝可用来制备高纯镁铝尖晶石,也可以直接用作催化剂,有着广阔的开发前景。     

Study on Synthesis Technology of Mg-Al Double Alkoxides

介绍了镁铝双金属醇盐的合成方法,详细介绍和评述了乙醇镁铝、异丙醇镁铝、正丁醇镁铝、异丁醇镁铝等双金属醇盐的合成工艺.正丁醇镁铝、异丁醇镁铝可用来制备高纯镁铝尖晶石,也可以直接用作催化剂,有着广阔的开发前景.     

抗水合氧化铝载体研究进展

氧化铝系载体用于含水或有水生成的催化过程时，均会发生再水合现象，从而造成催化剂强度的下降，并导致其比表面积大幅下降，使催化剂不可逆失活。镁铝尖晶石的抗水合性远高于氧化铝系载体，是一种很好的催化剂载体。综述了氧化铝系载体的再水合现象、改进载体抗水合性能的方法以及镁铝尖晶石粉体和载体的制备方法及改进措施。     

以镁铝尖晶石为载体的Fe-Cr高变催化剂的研制

以镁铝尖晶石为载体，溶胶法制备的γ-Fe2O3，制备了纳米级负载型Fe-Cr高变催化剂。研究了制备条件对镁铝尖晶石性能的影响；γ-Fe2O3制备过程中乙二醇与硝酸铁的比例及反应条件对溶胶粒径及吸附性能的影响。研究了氧化铁的晶形、负载量、助剂量及催化剂热处理条件等因素对催化剂性能的影响。     

镁铝尖晶石和铬矿对镁质浇注料烧结的影响

研究了加入镁铝尖晶石和铬矿砂对SiO2微粉结合镁质浇注料烧结的影响。结果表明:(1)加入适量的镁铝尖晶石或铬矿砂对于提高镁质浇注料的烧结程度和强度均有较明显的作用,但加入量不能太多,在本试验条件下,加入镁铝尖晶石和铬矿砂的最佳质量分数分别为12%和10%;(2)加入镁铝尖晶石的镁质浇注料在强度方面要好于加入铬矿砂的;(3)加入的镁铝尖晶石作为晶种,促进了亚白刚玉粉和α-Al2O3微粉在镁质浇注料中生成镁铝尖晶石,铬矿砂的加入则生成了大量的镁铬尖晶石和少量的镁铝铬尖晶石。     

草酸镁的合成与应用研究

分别概述了以金属Mg、氢氧化镁、硝酸镁、硫酸镁、氯化镁、乙酸镁等为原料制取草酸镁的合成方法,详细介绍了草酸镁作为催化剂和作为制取镁铝尖晶石、纳米氧化镁的前驱物等方面的应用现状。草酸镁有着广阔的应用和发展前景。     

多孔片状镁铝尖晶石的制备

在催化剂载体和吸附等领域,具有介孔结构的片状镁铝尖晶石因比表面积大、活性位点丰富、不易团聚等特性,受到越来越多的关注。以铝丝为铝源、镁粉为镁源、无水乙醇为溶剂,Na2Mo O4为熔盐,采用熔盐辅助非水解溶胶–凝胶法制备多孔片状镁铝尖晶石。借助X射线衍射仪、场发射扫描电子显微镜等测试手段研究了热处理温度及保温时间对镁铝尖晶石合成与形貌的影响,运用透射电子显微镜(TEM)观察片状晶体的微观结构,采用氮气吸附脱附测试对样品的比表面积和孔径进行了表征。结果表明：热处理温度和保温时间均对镁铝尖晶石形貌有较大影响。优选热处理温度为900℃,保温时间为8 h,可制备出具有介孔结构的片状镁铝尖晶石,片的长度为140～160 nm。所制得样品的比表面积为76 m2/g。TEM和氮气吸附脱附曲线测试结果表明,样品存在明显的介孔结构。为制备多孔片状镁铝尖晶石提供了一种新思路。     

MgAl2O4透明陶瓷粉体的研究进展

透明镁铝尖晶石陶瓷的制备,对粉体有特殊的要求.高纯、超细、分散性好、高活性的粉体是制备镁铝尖晶石透明陶瓷的首要条件.本文以制备镁铝尖晶石透明陶瓷为目标,从粉体的纯度和粉体颗粒特征两方面分析了粉体的性能对制备透明镁铝尖晶石陶瓷的影响,介绍了几种可用于制备镁铝尖晶石透明陶瓷粉体的方法,分析比较了每种方法的优缺点.     

用等离子熔渣回收过程产生的残渣制取镁铝尖晶石耐火材料

用等离子熔渣回收过程产生的熔融残渣制取的镁铝尖晶石砖，其性能可与工业用产品媲美。熔融残渣主要含氧化铝，氮化铝和氧化镁，这种残渣首先经过回转窑的高温煅烧，继之在等离子交换炉中熔融，而被转化成尖晶石熟料。通过改变熔融产物的化学组成，可得到化学计算和非化学计算的镁铝尖晶石，以此生产的镁铝尖晶石砖的质量与水泥回转窑过渡带使用砖的标准质量不相上下，这些产品用物理、机械和高温性能来表示其特性，使用光学和扫描电     

Oxygen vacancy engineering on copper-manganese spinel surface for enhancing toluene catalytic combustion: A comparative study of acid treatment and alkali treatment

Copper-manganese spinel is a low-cost VOCs catalytic combustion catalyst with good performance. Oxygen vacancy has excellent properties for oxygen activation and VOCs dehydrogenation activation, which is beneficial for the catalytic combustion of VOCs. In this study, a large number of oxygen vacancies were introduced on the copper-manganese spinel surface by selective dissolution method (acid treatment and alkali treatment) for catalytic combustion of toluene. Furthermore, the effects of acid treatment and alkali treatment on the catalytic performance, oxygen vacancy amount, physical and chemical properties, and toluene catalytic combustion mechanism of copper-manganese spinel were studied. Both acid treatment and alkali treatment can produce large quantities of oxygen vacancies on the copper-manganese spinel surface. The generation of surface oxygen vacancies can greatly improve the catalytic combustion activity of copper-manganese spinel. At 240 °C, the combustion rate of toluene increased by 8.8 times for the acid-treated catalyst and 11.2 times for the alkali-treated catalyst. The numerous surface oxygen vacancies, Mn³⁺/Mn⁴⁺ at the ratio of 1.11 and appropriate acidity result in the alkali-treated catalyst exhibiting excellent catalytic activity and stability for toluene combustion. This strategy provides a new method to further improve catalytic combustion activity of copper-manganese spinel and a reference for the development of the surface oxygen vacancy engineering of transition metal oxides.     

Effect of preparation method on structure and catalytic activity of Cr-promoted Cu catalyst in glycerol hydrogenolysis

Relationships between surface structure and catalytic properties were investigated for a series of copper chromium catalysts. The catalysts were prepared using methods involving impregnation and precipitation, and their catalytic activities were evaluated for the hydrogenolysis of glycerol. Catalyst (10I and 50I) prepared by the impregnation method contained a mixed phase of both individual copper and chromium oxide structures, while the catalyst (50P) prepared by precipitation showed a single phase, with a copper chromite spinel structure (CuCr₂O₄). XPS data indicated that, after the reduction step, the copper species in the impregnated catalyst was reduced to Cu⁰, but the catalyst prepared by the precipitation method retained a spinel structure evidenced by the large amount of Cu²⁺ species. In hydrogenolysis reactions, the precipitated catalyst showed a higher catalytic activity than the impregnated catalyst. Thus, the reduced copper chromite spinel structure, which constitutes a single phase, appears to be responsible for the high catalytic activity in the hydrogenolysis of glycerol to propylene glycol.     

2,6-二甲基苯酚气相胺化催化剂的研制

研制了2,6-二甲基苯酚气相胺化合成2,6-二甲基苯胺催化剂Pd/尖晶石，考察了不同γ-Al₂O₃载体和尖晶石的组成对催化剂催化活性的影响，同时研究了反应温度对催化反应的影响。     

Influence of mixing time during glycine–nitrate process on the structural properties and reducibility of a dual-phase Ni–Cu–Mn spinel catalyst

The potential of Ni–Cu–Mn spinels as methane reforming catalysts for hydrocarbon-fueled solid oxide fuel cell (SOFC) applications is highly dependent on its catalytic properties, particularly reducibility. The reducibility of a spinel-structured catalyst is often correlated with its structural properties and fabrication processes. In this work, the structural properties and reducibility of a Ni–Cu–Mn spinel catalyst was evaluated on the basis of mixing time during the glycine–nitrate process. Phase analysis results showed that Ni_0.4Cu_0.6Mn_2.0O₄ and (Cu, Mn)₃O₄ in normal or inversed spinel structures were observed in GNP-produced Ni–Cu–Mn spinel catalyst powders. Distortion in inverse spinel structures enhanced the reducibility of the spinel catalyst. Morphological analysis results showed that complete nitrate binding occurred at a minimum mixing time of 24 h and resulted in homogenous particle size distribution and uniform elemental distribution. Furthermore, the Ni–Cu–Mn spinel catalyst produced after 24 h of mixing was fully reduced at 450 °C. The reducing pattern of the Ni–Cu–Mn spinel catalyst produced after 24 h of mixing time showed strong metal–support interaction and the fast adsorption of reactants. These effects were due to either the distribution of divalent cations in octahedral sites or large amounts of bulk pores. In conclusion, a minimum mixing time of 24 h is sufficient to produce the desired structural properties and reducibility of Ni–Cu–Mn spinel catalysts for SOFC applications.     

铁氧体催化剂磁性合成及其对双氧水分解反应的影响

通过双氧水催化分解反应动力学研究,显示磁化合成铁氧体具有较高的催化速率.利用高分辨分析电镜和电子能量损失谱测试了其显微形貌、化学组成和微区晶体结构,探讨了催化作用机理.     

尖晶石型Mn_(1-x)M_xCo_2O_4柴油车尾气处理催化剂的制备及其应用

尖晶石型复合氧化物因具有独特的结构特征而成为相对理想的柴油车尾气处理催化剂。采用溶胶-凝胶法制备尖晶石型Mn_(1-x)M_xCo_2O_4催化剂,通过X射线衍射(XRD)和程序升温氧化(TDO)等对Mn_(1-x)M_xCo_2O_4催化剂进行表征。结果表明,制备的样品Mn_(1-x)M_xCo_2O_4均为尖晶石型复合氧化物;掺杂Cu、Ce后,催化剂的氧化性能有不同程度的变化。在固定床微型反应器上对催化剂催化活性进行评价,结果表明,与纯MnCo_2O_4相比,Mn_(0.9)Ce_(0.1)Co_2O_4催化剂催化活性提高,Mn_(0.9)Cu_(0.1)Co_2O_4催化剂催化活性降低,但CO_2选择性增加。     

In situ combustion synthesis of structured Cu-Ce-O and Cu-Mn-O catalysts for the production and purification of hydrogen

The combustion method was employed for the in situ synthesis of nanocrystalline Cu-Ce-O and Cu-Mn-O catalyst layers on Al metal foam, without the need of binder or additional calcination steps. Copper-manganese spinel oxides have been proposed as a catalytic system for hydrogen production via methanol steam reforming, while CuO-CeO₂ catalysts have been successfully examined for CO removal from reformed fuels via selective oxidation. In this work, the performance of these catalysts supported on Al metal foam has been investigated in the reactions of methanol reforming and selective CO oxidation. The Cu-Ce-O foam catalyst exhibited similar catalytic performance to the one of the powder catalyst in the selective oxidation of CO. The performance of the Cu-Mn-O foam catalyst in the steam reforming of methanol was inferior to the one of the powder catalyst at intermediate conversion levels, but almost complete conversion of methanol was obtained at the same temperature with both foam and powder catalysts.     

CoAl2O4 spinel catalyst for soot combustion with NOx/O2

Mesoporous and nanosized cobalt aluminate spinel with high specific surface area was prepared using microwave assisted glycothermal method and used as soot combustion catalyst in a NO_x + O₂ stream. For comparison, zinc aluminate spinel and alumina supported platinum catalysts were prepared and tested. All samples were characterised using XRD, (HR)TEM, N₂ adsorption–desorption measurements. The CoAl₂O₄ spinel was able to oxidise soot as fast as the reference Pt/Al₂O₃ catalyst. Its catalytic activity can be attributed to a high NO_x chemisorption on the surface of this spinel, which leads to the fast oxidation of NO to NO₂.     

Preparation and catalytic activity in ethanol combustion reaction of cobalt–iron spinel catalysts

Iron–cobalt spinel catalysts were prepared via the coprecipitation method. The effect of different parameters on textural, structural and catalytic properties, in ethanol combustion, was investigated. The CoFe₂O₄ phase was obtained at calcination temperatures as low as 500 °C and the usage of ammonia as precipitating agent, results in the formation of Fe₂O₃ in addition to the spinel phase. The catalyst prepared using nitrate salts, NaOH as precipitation agent and calcined at 600 °C had the best catalytic performance achieving ethanol complete oxidation at 271 °C.