高分散纳米Y型分子筛负载Ni_2P催化剂的制备及其加氢脱硫性能

以无模板剂法合成的纳米Y型分子筛(35 nm左右)为载体,采用低温还原法制备了高分散Ni_2P/NY催化剂,同时制备了普通Y型分子筛担载的Ni_2P/Y催化剂作为对比。采用X射线衍射(XRD)、扫描电镜(SEM)、透射电镜(TEM)和X射线光电子能谱(XPS)等手段对载体和催化剂进行了表征,并在固定床反应器中考察了不同催化剂对4,6-二甲基二苯并噻吩(4,6-DMDBT)的加氢脱硫反应性能。结果表明,该催化剂的高活性来自纳米Y型分子筛上Ni_2P分散度的提高和高活性中心的暴露。在反应温度为340℃,反应压力为3.0 MPa的条件下,以Ni_2P/NY为催化剂,4,6-DMDBT的转化率达到了96.0%,高于CoMoS/Al_2O_3商业催化剂(77.2%)和Ni_2P/Y催化剂(67.0%)。     

Ni2P/TiO2上噻吩加氢脱硫性能研究

在10%H2/N2流动气氛下,用程序升温还原方法由相应的磷酸盐合成了二氧化钛负载磷化镍(Ni2P/TiO2)催化剂,用X射线衍射(XRD)、低温N2吸附(BET)等技术对催化剂的结构和性质进行了表征,在高压连续流动固定床反应装置上以噻吩为模型化合物,考察该催化剂的制备条件对其加氢脱硫性能的影响.结果表明,由Ni/P摩尔比为1/2和1/3的前驱体制备的催化剂表面仅出现Ni2P物相;由Ni/P摩尔比为1/1的前驱体制备的催化剂表面出现的主要物相为Ni2P,同时还存在少量Ni12P5相.催化剂的比表面积随前驱体中Ni和P含量的增加而减小.在温度370℃,压力3.0 MPa,VHSV为2 h-1,氢油比(v/v)为450的反应条件下,由Ni负载量为15%(wt)、Ni/P摩尔比为1/2的前驱体所制得Ni2P/TiO2催化剂对含硫0.1%(wt)油具有接近100%的脱硫转化率,并有良好的稳定性.加氢脱硫反应工艺条件研究结果表明:压力、液时进料体积空速以及氢油比对Ni2P/TiO2催化剂对噻吩加氢脱硫性能影响在较宽的范围内变化不大.反应温度对该催化剂上的噻吩加氢脱硫反应的影响较大,当反应温度高于300℃,催化剂对噻吩加氢脱硫性能达到接近100%的脱硫率.     

焙烧及还原条件对Ni2P/TiO2-Al2O3催化剂加氢脱硫性能的影响

采用溶胶-凝胶法制备了TiO₂-Al₂O₃复合载体, 以柠檬酸(CA)为络合剂采用浸渍法制备了Ni₂P负载的TiO₂-Al₂O₃复合载体催化剂, 并用 X 射线衍射(XRD)、N₂吸附比表面积(BET)测定技术对催化剂的结构和性质进行了表征, 考察了载体焙烧温度、催化剂焙烧温度、还原温度、还原压力对其进行的二苯并噻吩(DBT)加氢脱硫(HDS)性能的影响。结果表明, 升高载体焙烧温度有利于催化剂表面上活性物种的分散, 但焙烧温度过高会导致催化剂烧结, 适宜的载体焙烧温度为550℃。当还原温度为500～550℃时, 磷化镍主要以Ni₁₂P₅相形式存在, 且随着还原温度的升高, Ni₁₂P₅的衍射峰强度逐渐增强, 还原温度为700℃时, 可得到单一的Ni₂P物相。载体焙烧温度为550℃, 催化剂焙烧温度为500℃, 还原温度为700℃, 常压还原制备的Ni₂P/TiO₂-Al₂O₃催化剂具有最好的活性。在360℃、3.0MPa、氢油体积比500、液时体积空速2.0h^-1的条件下, 反应4h时, DBT转化率为99.5 %。     

制备条件对Ni2P/TiO2-Al2O3催化剂加氢脱硫性能的影响

采用溶胶-凝胶法制备了TiO₂-Al₂O₃复合载体, 以柠檬酸为络合剂, 浸渍法制备了负载型Ni₂P/TiO₂-Al₂O₃催化剂前体, 程序升温H₂还原法制备了Ni₂P/TiO₂-Al₂O₃催化剂, 并用 X 射线衍射(XRD)、N₂吸附比表面积(BET)测定技术对催化剂的结构和性质进行了表征, 考察了浸渍方法、Ni/P摩尔比、Ni₂P负载量对其进行的二苯并噻吩(DBT)加氢脱硫(HDS)性能的影响。结果表明, 当Ni/P比低于1:1时, 能得到单一的Ni₂P物相;当Ni/P比为2:1时, 开始出现Ni₃P物相。采用Ni/P比为1:1、Ni₂P负载量为30%、采用共浸渍方法制备的Ni₂P/TiO₂-Al₂O₃催化剂具有最好的活性, 在360℃、3.0MPa、氢油比500 (体积比)、液时体积空速2.0h^-1的条件下反应4h时, 二苯并噻吩转化率为99.5%。     

Ni2P加氢脱硫催化剂的研究进展

简述了Ni2P催化剂的结构与加氢脱硫机理,以及Ni2P催化剂的3种制备方法：程序升温还原法、液相法和次磷酸盐热分解法.重点介绍了近年来Ni2P催化剂载体的研究情况,指出开发高效节能的新型加氢脱硫催化剂具有重要意义.     

氢等离子体法制备Ni_2P催化剂及加氢脱硫性能

采用氢等离子体还原法制备了体相Ni2P,新鲜制备的Ni2P在移入固定床反应器之前用体积分数10%H2S/Ar钝化,以保护其结构不被破坏。实验证明:氢等离子体(PR)还原法制备的Ni2P催化剂的加氢脱硫活性高于程序升温还原(TPR)法制备的催化剂。XRD表征结果表明,氢等离子体还原法制备的Ni2P的粒度较小,活性中心较多,其高活性可归于其活性中心数量的增加。氢等离子体还原法制备的Ni2P具有良好的反应稳定性。     

Ni2P/TiO2的制备、表征及其加氢脱硫反应性能

利用程序升温还原方法合成了Ni2P／TiO2催化剂,采用H2-TPR、XRD、XPS等技术对样品的结构和性质进行了表征,研究了催化剂对噻吩的常压加氢脱硫反应性能。结果表明,在TiO2为载体的负载型催化剂上,Ni2P为主要活性相,无明显的单质Ni相;与Ni2P／SiO2相比,Ni2P／TiO2催化剂对噻吩常压加氢脱硫反应有较高的转化率以及良好的稳定性,噻吩稳定转化率达到了36％左右。     

Ni2P/ZrO2催化剂对苯酚的加氢性能

采用浸渍法及热分解法合成了不同负载量的Ni₂P/ZrO₂催化剂,通过XRD、TEM和氮气吸脱附等多种手段表征其物理化学性质,并通过对苯酚的加氢处理来研究载体对Ni₂P活性的影响。结果表明：Ni₂P分散负载在ZrO₂的表面,ZrO₂载体降低了Ni₂P的粒径,有效防止了Ni₂P的聚集,显著提高了Ni₂P对苯酚加氢脱氧的活性。在相同催化条件下,10%-Ni₂P/ZrO₂呈现出最佳催化活性。以10%-Ni₂P/ZrO₂为代表考察催化反应最优条件,在反应温度300℃、初始氢气压5MPa下反应2h,苯酚转化率达到90.8%,环己烷选择性达到91.7%。     

MoO3/TiO2催化剂的二苯并噻吩加氢脱硫性能

以介孔氧化钛晶须成型材料为载体,通过浸渍法制备不同MoO3负载量的MoO3/TiO2加氢脱硫催化剂. XRD分析表明,介孔氧化钛晶须成型载体为纯锐钛矿相,MoO3负载量为7.2%(w)的催化剂未出现MoO3的衍射峰;BET分析显示,负载7.2%(w) MoO3后,氧化钛晶须成型载体的比表面积和孔容能保持原来的80%以上. 活性评价结果表明,未经预硫化的MoO3/TiO2催化剂直接应用于二苯并噻吩(DBT)加氢脱硫反应时,在温度280~300℃、氢分压2.0 MPa、体积空速4 h-1、H2/油体积比600的条件下,DBT转化率达100%. 将模型溶液中硫含量由400′10-6 g/g降至10′10-6 g/g以下,催化剂表现出较高的活性,且在一定条件下运行1000 h未出现失活迹象.     

磷化镍调变MoS2/γ-Al2O3催化剂的加氢脱硫性能

引言 随着人们环保意识的增强,世界各国相继颁布了更为严格的成品油硫含量标准.目前主要国家的车用柴油标准要求硫含量不大于500 μg·g-1,而未来柴油硫含量将控制在30～50 μg·g-1[1].     

The Effect of CeO2 on the Hydrodenitrogenation Performance of Bulk Ni2P

Bulk Ni₂P and CeO₂-containing bulk Ni₂P (Ce?CNi₂P(x), where x represents the Ce/Ni atomic ratio) were prepared by a co-precipitation method followed by an in situ H₂ temperature-programmed reduction procedure. The catalysts were characterized by XRD, CO chemisorption, TEM, N₂ adsorption?Cdesorption, XPS and X-ray absorption spectroscopy (XAS). Their hydrodenitrogenation performances were studied using quinoline (Q) and decahydroquinoline as the model compounds. Both the hydrogenation and C?CN bond cleavage activities of Ni₂P were improved by the introduction of CeO₂. CeO₂ mainly accelerated the denitrogenation of Q to propylcyclohexane rather than to propylbenzene. XRD and XPS measurements revealed that the Ce species in Ce?CNi₂P(x) were mainly in the oxide form and both Ce⁴⁺ and Ce³⁺ species coexisted on the surface of the catalysts. Addition of CeO₂ significantly decreased the particle size of Ni₂P, resulting in increased specific surface areas and CO uptakes, possibly due to the strong interaction between the Ce species and Ni₂P. At a Ce/Ni atomic ratio higher than 0.25, segregation of CeO₂ took place. XAS results of the passivated catalysts showed that CeO₂ not only affected the oxidability of Ni₂P but also led to the formation of metallic Ni. The promoting effect of CeO₂ was discussed by considering the electronic interactions between Ce species and Ni₂P as well as the presence of the amorphous Ni and low valence Ce³⁺ species.     

Ni_2P/TiO_2-Al_2O_3负载催化剂加氢脱硫催化性能研究

利用溶胶-凝胶手段制备了Ti O_2改性的Al_2O_3复合载体,并借助共沉积法制备了多种具有不同担载量的Ni2P/Ti O_2-Al_2O_3催化剂,通过X射线衍射、扫描电镜和红外光谱等技术手段相结合对复合载体和催化剂进行了结构的表征和确证,以二苯并噻吩作为目标物考察不同担载量条件下催化剂加氢脱硫反应活性的变化。结果表明,Ni2P/Ti O_2-Al_2O_3负载催化剂能够在较低的Ni2P负载量时就具有非常优异的催化活性和良好的长期稳定性,将其应用于加氢脱硫反应能够达到非常高的转换效率。     

NiMoS/ZSM-5-MCM-41催化剂的制备及其加氢脱硫性能

以十六烷基三甲基溴化铵作为模板剂,将ZSM-5用不同浓度NaOH处理脱硅,并利用重结晶法成功合成了具有较强酸性的ZSM-5-MCM-41复合分子筛[记为ZMC-M(x),M=1.5、2.0、2.5,x=n(SiO_2)/n(Al_2O_3)]。然后,采用浸渍法制备了Mo S2/ZMC和Ni-MoS_2/ZMC催化剂。考察了不同浓度NaOH脱硅对复合分子筛ZMC结构和性质的影响。同时以噻吩为模型化合物,考察了ZMC的硅铝比、NiMo双金属硫化物对噻吩加氢脱硫的影响。结果表明,随着NaOH浓度的增加,复合分子筛ZMC会生成更多的介孔相,但是过高浓度NaOH处理后会破坏ZSM-5的结构,确定了最佳NaOH处理浓度为2.0 mol/L。随着ZMC硅铝比的增加,催化剂加氢脱硫活性提高,并且复合分子筛负载Ni Mo双金属硫化物的加氢脱硫性能优于复合分子筛负载MoS_2。在H2压力3 MPa、温度280℃、40 mL(1 mg/L)噻吩/十四烷溶液中,0.1 g的20%MoS2/ZMC-2.0(70)和20%Ni-MoS2/ZMC-2.0(70)[m(Mo)∶m(ZMC)=1∶5,n(Ni)∶n(Mo)=1∶1]催化剂对噻吩的转化率分别达到84.1%和95.2%。     

Preparation,Structure Characterization and Hydrodesulfurization Performance of B-Ni2P/SBA-15/Cordierite Monolithic Catalysts

A series of B-Ni2P/SBA-15/cord monolithic catalysts were prepared by coating the slurry of the B-Ni2P/SBA-15 precursors on a pretreated cordierite support, and followed by temperature-programmed reduct...     

Ni_2P/TiO_2-Al_2O_3催化剂的放大制备及其深度加氢脱硫性能

按照单位体积搅拌功率恒等的放大准则,采用不同规格的反应釜以溶胶凝胶法(sol-gel)制备Ti O2-Al2O3复合载体;依据还原气体线速度恒等的放大准则,在不同规格管式炉中以程序升温还原法(TPR)制备Ni2P/Ti O2-Al2O3催化剂,并在连续固定床反应器中考察催化剂的加氢脱硫性能,以研究凝胶、TPR这两个催化剂制备关键过程的"放大效应"。结果表明,放大制备的载体物化性质与小试结果相当,放大制备的催化剂在温度603 K、压力2.5 MPa、质量空速2 h?1、氢油体积比500的条件下对含硫量为0.1%(wt)的二苯并噻吩(DBT)/环己烷溶液进行90 h的加氢脱硫反应,转化率达到99.4%,模型油品中硫含量降至6 ppm,其结果也与小试相同,表明上述载体以及催化剂制备工艺可靠、重复性好,有望实现规模化制备。     

Hydrodesulfurization of Dibenzothiophene and its Hydrogenated Intermediates Over Bulk Ni2P

A bulk Ni₂P catalyst was prepared by co-precipitation of nickel phosphate followed by in situ temperature-programmed reduction (TPR) with H₂. The hydrodesulfurization (HDS) of dibenzothiophene (DBT) and its hydrogenated intermediates 1,2,3,4-tetrahydro-dibenzothiophene (TH-DBT) and 1,2,3,4,4a,9b-hexahydro-dibenzothiophene (HH-DBT) was studied at 340 °C and 4 MPa both in the presence and absence of piperidine (Pi). Bulk Ni₂P exhibited a relatively low hydrogenation/dehydrogenation activity but high desulfurization activity. Pi retarded the hydrogenation of DBT to a greater extent than the desulfurization. The desulfurization of HH-DBT to 2-cyclohexen-1-yl-benzene (CHEB-2) occurred mainly by ??-elimination of the hydrogen atom attached to carbon atom C(4), whereas TH-DBT desulfurized mainly by hydrogenolysis to 1-cyclohexen-1-yl-benzene (CHEB-1). A minor amount of biphenyl (BP) observed in the HDS of TH-DBT and HH-DBT is due to the disproportionation of cyclohexenyl-benzenes. A reaction network of the HDS of DBT over Ni₂P is postulated in which both ??-elimination and hydrogenolysis play a role in the breaking of the C?CS bonds.     

Hydrodechlorination of Chlorobenzene Over Ni2P/SiO2 Catalysts: Influence of Ni2P Loading

The influence of Ni₂P loading on the properties of Ni₂P/SiO₂ catalysts was investigated by means of N₂ adsorption–desorption, X-ray diffraction, H₂ and NH₃ temperature-programmed desorption, CO chemisorption, inductively coupled plasma atomic emission spectroscopy and activity evaluation for the hydrodechlorization of chlorobenzene. It was found that increasing Ni₂P loading results in the decrease of Ni₂P dispersion. Higher P/Ni ratio occurs in the catalysts with lower Ni₂P loadings, indicating that smaller Ni₂P crystallites may more strongly interact with surplus P. We suggest that the acid amount of the Ni₂P/SiO₂ catalyst is related to the exposed Ni sites and P-OH groups, while Brönsted acidity of P-OH groups facilitates hydrogen spillover. Increasing Ni₂P loading is favorable to the catalyst activity, while this effect is not obvious when the Ni₂P loading is greater than 9.6 wt%. Apart from the metallic property of Ni₂P phase and spilt-over hydrogen species, we propose that the acidity and the role of P in activating reactants should be considered for the catalyst performance.     

Hydrogen Production from Ethanol Steam Reforming Over Ni/CeO2 Nanocomposite Catalysts

The organic polymer chitosan was used as the polymeric precursor for the synthesis of Ni/CeO₂ nanocomposite catalysts. The materials were characterized by N₂ physisorption, H₂ chemisorption, AA, XRD, TGA, TPR, SEM and TEM analyses. The catalysts provide very good reactivity in ethanol steam reforming compared to the conventional Ni/CeO₂ catalyst prepared by the impregnation method using a commercial support. High hydrogen selectivity (>75%) was obtained on Ni/CeO₂ catalysts by operating at a temperature range of 325–500 °C and a H₂O/C₂H₅OH molar ratio of 3. It was verified that the catalytic behavior could be influenced depending on the experimental conditions employed.     

Structural Features and Catalytic Properties of Pt/CeO2Catalysts Prepared by Modified Reduction-Deposition Techniques

The structural features and catalytic properties of Pt/CeO₂catalysts prepared by liquid phase reduction-deposition techniques with formaldehyde and ethylene glycol as reducing agents, respectively, were investigated. TPR and CO pulse titration measurements revealed that smaller particle size and uniform dispersion of platinum were achieved by modified polyol preparation process, which is beneficial to generate appropriate Pt-O-Ce chemical bonding. XPS analysis further demonstrated the presence of strong metal-support interaction in above Pt/CeO₂catalyst. It was observed that the reducing ability and the solvent effect play important roles in controlling the formation of nuclei as well as its growth rate. The sample prepared by modified polyol method exhibited higher catalytic activities and longer stability for the complete oxidation of dimethyl ether than Pt/CeO₂catalyst prepared by HCHO liquid phase reduction.