过渡金属磷化物的制备和催化性能研究

原油的重质化和日益严格的环境法规使燃料油加氢精制技术面临新的挑战。过渡金属磷化物由于具有优异的加氢脱硫、加氢脱氮活性和稳定性成为催化材料领域研究的焦点。本文综述了过渡金属磷化物的制备方法、催化性能和活性相,在加氢脱硫过程中过渡金属磷化物表层可能被硫化形成磷硫相,这可能与磷化物的催化活性和稳定性有关。过渡金属磷化物催化剂有望成为MoS2催化剂之后的又一代深度加氢脱硫催化剂。     

过渡金属磷化物的催化加氢脱硫机理研究进展

本文综述了含硫化合物在体相、负载以及改性的过渡金属磷化物催化剂上的加氢脱硫机理研究,讨论了催化剂的结构-活性之间的关系,以及不同类型磷化物对含硫化合物在催化剂上的反应路径的影响。同时,一些研究中不同阶段速率常数的计算让我们对反应步骤有了更深入的认识,并对含硫化合物在磷化物催化剂上的反应动力学和反应网络有了进一步了解,为新型磷化物深度加氢脱硫催化剂的开发和应用提供理论基础,具有重要的学术价值和普遍指导意义。     

介孔碳负载高分散Fe-P催化剂的制备及其催化硝基苯加氢性能研究

开发低成本和高性能的加氢催化剂对于基础研究和工业应用具有重要意义。采用浸渍-热解策略，将Fe3+-植酸的络合物负载到介孔碳（MPC）表面热解处理，实现了一步法合成磷掺杂碳负载金属催化剂，并可通过调节Fe和植酸比例制得一系列具有不同结构的Fe-P/MPC催化剂。结合XPS、XRD、BET、SEM和TEM等表征技术，发现高分散的Fe-P催化剂（0.1Fe-P/MPC）具有最优的硝基苯加氢催化活性（TOF = 334 h-1），相较于单原子Fe1-P-C催化剂，活性提升了约7倍，同时该催化剂也展现出较高的稳定性，循环使用5次活性未见明显下降；而纳米金属磷化物Fe2P（0.5Fe-P/MPC）则几乎没有加氢活性。     

磷前驱体对金属磷化物甲烷化催化性能的影响（英文）

采用氢气程序升温还原方法制备了系列金属磷化物催化剂,研究了磷前驱体和H_2/CO比对其甲烷化催化性能的影响。结果表明,与磷酸氢二铵相比,由植酸制备的金属磷化物催化剂具有较高的甲烷化活性;植酸作为螯合剂可以有效地分散金属前驱体,降低还原温度,使催化剂具有较高的比表面积和较小的晶粒尺寸,并更好地还原为纯磷化物晶相。不同金属磷化物催化剂的活性顺序为MoP WP CoP NiP。高H_2/CO比有利于甲烷化反应进行,随着反应物H_2/CO比的增加,所有磷化物催化剂的甲烷选择性都增加。     

氮、磷、碳化物比较研究初探

环保法规的日益严格使得研究者越来越重视新型加氢脱硫、脱氮催化剂的开发。国内外学者在对负载型Mo—Co、Mo—Ni和W—Ni等传统硫化物催化剂进行不断改进的同时，新型催化材料尤其是具有贵金属性质的过渡金属间充化合物一氮化物、碳化物和磷化物的研究也受到很大的关注。人们在探索不同的载体或者是不同的助剂对单金属间充化合物-氮化物、碳化物或磷化物催化剂活性组分的表面状态和结构以及其深度加氢脱硫脱氮性能的影响，而对同一载体负载的氮、磷、碳化物催化剂缺乏横向的比较。本研究制备了以γ-Al2O3为载体的负载型氮化钼、磷化钼和碳化钼催化剂，比较了它们的孔结构、比表面积，并初步分析了钼的质量分数为19％，氮化、磷化和碳化温度均为650℃时三类催化剂的二苯并噻吩加氢脱硫性能。     

加氢脱氮催化研究的新进展

化石燃料的加氢脱氮有利于改善油品质量及其稳定性，同时避免燃烧时NO_x的排放。本文介绍了不同化石燃料中有机氮化物的含量及类型，对不同加氢脱氮催化剂及其催化活性位的本质进行了探讨，同时论述了C—N键断裂机理及燃料中主要有机氮化物的HDN反应网络。着重概述了传统金属硫化物催化剂的改性方法，新型的金属碳化物、金属氮化物和金属磷化物催化剂的研究现状。     

低温熔融盐合成富磷相CuP_2纳米材料及其储锂应用

正纳米过渡金属磷化物(MP_x,M=Cu,Ni,Fe,等)在电催化,光催化,超级电容器以及锂离子电池等领域具有很大的应用前景~(1–3)。在储锂应用中,过渡金属磷化物的理论容量与磷的含量成正比,因此富磷的过渡金属磷化物最具吸引力。但目前富磷MP_x的合成比较困难,往往需要特殊的合成条     

过渡金属磷化物的制备及其催化性能研究进展

近来,廉价而丰富的磷化物逐渐引起人们的关注,过渡金属磷化物(TMPs)由于其独特的类金属理化性质、高电导率和良好的催化性能而非常具有吸引力,广泛应用于冶金、加氢处理、电催化、能量储存、光催化等领域,成为催化材料领域的热点。本文主要综述了TMPs的结构特征、常用的制备方法以及在加氢精制、电催化和光催化方面应用的最新进展。     

水电解制氢非贵金属催化剂的研究进展

氢能作为零碳排放能源是被公认的最清洁能源之一,如何有效可持续地产氢是未来人类步入氢能经济首先要解决的问题。电解水技术基于电化学分解水的原理,利用可再生电能或太阳能驱动水分解为氢气和氧气,被认为是最有前途和可持续性的产氢途径。然而,无论是光解水还是电解水,均需要高活性、高稳定性的非贵金属氢析出和氧析出催化剂以使水电解反应经济节能。本文介绍了我们研究所近三年在水电解方面的研究进展,其中着重介绍了:(i)氢析出催化剂,包括利用低温磷化过渡金属(氢)氧化物的方法制备过渡金属磷化物,同时过渡金属硫化物、硒化物以及碳化物等均被成功合成并被应用为有效的阴极析氢催化剂;(ii)氧析出催化剂,主要包括金属磷化物、硫化物、氧化物/氢氧化物等;(iii)双功能催化剂,主要包括过渡金属磷化物、硒化物、硫化物等。最后,总结展望了发展水电解非贵金属催化剂所面临的挑战与未来发展方向。     

自支撑型过渡金属磷化物电催化析氢反应研究

氢能作为一种零碳排放的清洁能源,主要通过电解水的途径获得。电解水析氢过程所使用的贵金属Pt基催化剂非常稀缺和昂贵,因此开发具有高活性和稳定性的非贵金属催化剂仍然是一个巨大的挑战。自支撑型过渡金属磷化物析氢性能优异,加之有效结合了自支撑基底的诸多优势,有望成为可替代贵金属Pt基催化剂的优良析氢材料。本文详细介绍了自支撑型过渡金属磷化物的研究进展,着重论述了此类型电催化剂的析氢优势及作用机理:(1)自支撑基底3D集成框架导电性较强,可提供大量的电子转移通道,从而加速催化反应进程;(2)自支撑型过渡金属磷化物较大的比表面积将会暴露出更多的活性位点,进而促进催化反应的发生;(3)自支撑型过渡金属磷化物可以直接作为阴极进行析氢反应,避免传统涂覆法中催化剂容易从玻碳电极脱落的弊端。最后,总结了此类型电催化剂用于电解水反应所面临的问题和挑战,并进行了合理的展望。     

Effect of Reduction Temperature on Hydrofining Performance of Supported Molybdenum Phosphide Catalyst

A series of supported molybdenum phosphide catalysts were prepared by impregnation method. XRD, TG-DTG, XPS and BET were used to study the phase, compositions and surface areas of the prepared catalysts. A model reactant containing thiophene, pyridine and cyclohexene was used for the measurements of catalytic activities. The effect of reduction temperature on catalytic activities was investigated. The analysis results by XRD and BET are very different when the reduction temperature is changed from 400 to 900 ℃. MoP/γ-Al2O3 catalysts and CoMoP/γ-Al2O3 catalysts prepared at the reduction temperature of 500 ℃ are the most active ones.     

三氟化硼修饰载体负载茂金属催化乙烯聚合

用BF3对载体硅胶和氧化铝进行了表面修饰,考察了修饰的载体负载茂金属催化剂后催化乙烯聚合的特性.研究表明,用BF3修饰过的载体负载二氯二茂锆催化乙烯的聚合,聚合活性有较大提高,具有工业应用前景,并且提出了这一催化体系的负载机理.     

溶胶-凝胶法制备MoP/SiO2催化剂加氢脱硫催化活性的研究

以正硅酸乙酯为硅源,以钼酸铵和磷酸二氢铵为钼源和磷源,采用溶胶-凝胶法,经干燥、焙烧,程序升温还原制备得到二氧化硅负载磷化钼(MoP)催化剂。以噻吩、二苯并噻吩为模型化合物,对负载催化剂的加氢脱硫活性进行评价,考察了负载量、反应压力、反应温度等因素对催化活性的影响。实验结果表明,MoP/SiO₂催化剂Mo的最佳负载量为20%,升高反应压力和温度均有利于提高二苯并噻吩的转化率,但降低了产物中联苯的含量。     

Sonochemical preparation of supported hydrodesulfurization catalysts

Sonochemical preparation of Co and Ni promoted MoS(2) supported on alumina was achieved by high-intensity ultrasonic irradiation of isodurene solutions containing molybdenum carbonyl, dicobalt octacarbonyl, elemental sulfur, and Al(2)O(3) or Ni-Al(2)O(3) under Ar flow. The sonochemically prepared catalysts were characterized by elemental analysis, XPS, SEM, TEM, and XEDS, and hydrodesulfurization (HDS) activity evaluated for thiophene and dibenzothiophene substrates. The TEM studies on the sonochemically prepared catalysts indicate the formation of layered hexagonal MoS(2) (lattice fringes approximately 6.2 A) on the alumina support. The sonochemically prepared Co-Mo-S/Al(2)O(3), Ni-Mo-S/Al(2)O(3), and Co-Ni-Mo-S/Al(2)O(3) are extremely active catalysts for the HDS of thiophene and dibenzothiophene, with activities severalfold those of comparable commercial catalysts under identical conditions. The layered structure of MoS(2) remained intact after 120 h of HDS, and the catalyst is reusable.     

Ni2P/TiO2的制备及其对苯加氢反应的催化性能

采用程序升温还原方法制备了TiO2负载的晶态Ni2P催化剂。用X射线衍射（XRD）及低温N2吸附（BET）等技术对样品的物相、比表面积等性质进行了表征。以苯气相加氢为模型反应考察了Ni2P/TiO2催化剂加氢性能，并对Ni2P负载量、前驱体中P的质量分数对催化剂的物相及性能的影响进行了研究。实验结果表明， TiO2负载的晶态磷化镍催化剂上，Ni2P是主要物相。Ni2P/TiO2催化剂对苯加氢反应具有较高的活性、选择性以及良好的稳定性能。Ni2P/TiO2制备对催化剂的性能有影响。Ni2P负载量增加，催化剂的活性先升高后降低，Ni2P负载量为12%时催化剂活性较高。催化剂前驱体中P的质量分数越高，制备出的催化剂对苯加氢反应的稳定性越好，但随前驱体中P的质量分数增加，催化反应的活性先升高，后降低。与Ni2P/SiO2比较，Ni2P/TiO2催化剂具有较高的活性和稳定性。     

Thiophene Hydrogenation to Tetrahydrothiophene over Tungsten Sulfide Catalysts

Independent reactions of thiophene reduction to tetrahydrothiophene and thiophene hydrogenolysis to form hydrogen sulfide and C₄ hydrocarbons are shown to occur over supported tungsten sulfide catalysts and unsupported tungsten sulfide at an elevated temperature and a high pressure. The highest rate of tetrahydrothiophene formation over the supported catalysts is observed when alumina was used as a support, and the lowest reaction rate is found when silica gel was used as a support. Both catalysts are less active than unsupported tungsten disulfide. The rate of thiophene hydrogenation over tungsten disulfide increases with increasing thiophene concentration and hydrogen pressure and is inhibited by tetrahydrothiophene. The selectivity to tetrahydrothiophene is constant (70–90%) in the whole range up to high thiophene conversions. The high selectivity over tungsten sulfide catalysts is suggested to be due to the reaction pathway through thiophene protonation mediated with the surface SH groups and to the inhibition of hydrogenolysis.     

Solution combustion synthesis of Co oxide-based catalysts for phenol degradation in aqueous solution

Solution combustion using urea as a fuel was employed to synthesise Co oxide and Al(2)O(3)-, SiO(2)- and TiO(2)-supported Co oxide catalysts. The catalysts were characterised using several techniques such as N(2) adsorption/desorption, XRD, FTIR, UV-vis diffuse reflectance and SEM-EDX, and their catalytic activity was evaluated in phenol degradation in aqueous solution with sulphate radicals. Solution combustion is a simple and effective method in preparation of supported Co catalysts. Co(3)O(4) was the major Co crystal phase in the samples prepared via the combustion synthesis. Bulk Co(3)O(4) particles were not effective in reaction, but supported Co oxides showed higher activity than unsupported Co oxide. The supports influenced Co dispersion and catalytic activity. Co/TiO(2) exhibited the highest activity, but it deactivated much faster than other two supported catalysts. Co/SiO(2) showed a comparable activity to Co/Al(2)O(3) and the best stability among the three Al(2)O(3)-, SiO(2)- and TiO(2)-supported Co catalysts.     

Ni/Al2O3-SiO2催化剂对C4单烯烃加氢的催化性能

利用XRD、H2 TPR和孔结构的分析对C4馏分加氢催化剂Ni/Al2O3 SiO2进行了表征，在固定床反应器内对催化剂的活性进行了评价，并对加氢机理进行了讨论。结果表明，在Ni/Al2O3 SiO2催化剂表面至少存在两种活性中心，分别由体相NiO和高度分散的NiO还原产生。研制的催化剂对C4馏分加氢具有很高的活性和良好的稳定性，进口温度18.6℃时就可进行加氢，属于低温型加氢催化剂。在 C4单烯烃质量分数为74.85%、加氢压力为2.0MPa~2.7MPa、液时空速为1.0h－1~2.0h－1、氢油体积比为 300~450下，原料中单烯烃转化率在98%以上。催化剂连续运行342h，其活性基本保持不变。     

Characterization of Cinchonidine Doped Montmorillonite Supported Noble Metal Catalysts by Thermoanalytical Methods

The characterization of new cinchonidine doped K-10 montmorillonite supported noble metal catalysts is described. Our aim was the mapping of thermal stability of these new catalytic materials by thermogravimetry (TG), differential thermogravimetry (DTG) and differential thermoanalysis (DTA) methods accompanied by X-ray diffraction (XRD) measurements. The catalysts were prepared by various methods including conventional, microwave and ultrasonic treatments. They were characterized first by X-ray diffraction to verify the stability of montmorillonite crystal structure during preparation. Then, TG and DTG methods were applied to determine their stability under the experimental conditions usually applied. The main changes observed were the loss of water and the decomposition of the organic modifiers in the higher temperature region. The catalyst showed the best performance were prepared and characterized using microwaves and ultrasonic irradiation in order to get more insight to the effect of preparation methods on their stability. As a consequence, the catalysts were found to be stable and regenerable under 450-500 K, however, higher temperatures resulted in the complete destruction of the catalysts. This revised version was published online in July 2006 with corrections to the Cover Date.     

原料油中氮、硫体积分数及反应压力对加氢裂化催化剂积炭的影响

在高压连续流动微型反应器上对加氢裂化催化剂进行催速老化实验，用元素分析、傅里叶变换红外光谱（FTIR）、X-光电子能谱（XPS）、热重/微商热重（TG/DTG）等手段考察了不同体积分数的噻吩、吡啶和操作压力对催化剂积炭行为的影响。结果发现：原料中吡啶和噻吩体积分数分别高于0.1%和0.6%时，会导致催化剂积炭明显增加。含吡啶的原料在进行加氢裂化时生成的积炭，主要集中在微孔（<6 nm）中，并会削弱催化剂的酸性中心，尤其是强酸中心。含噻吩原料加氢裂化生成的积炭，存在于不同孔径的孔中，在催化剂表面形成少量机械孔。原料中噻吩体积分数低于0.6%时，噻吩中的硫可以提高催化剂的硫化度使积炭减缓。相同体积分数的吡啶对催化剂积炭的贡献大于噻吩，催化剂比表面积降低更多。提高压力可以显著地降低催化剂的积炭量，减缓比表面的降低，减少酸中心数目的损失，导致微孔（<6 nm）中积炭增多，积炭中石墨型积炭的相对比例增大。