Ni_2P/TiO_2-Al_2O_3催化剂的制备及其加氢脱硫、脱氮性能

采用溶胶-凝胶法制备了TiO2-Al2O3复合载体,采用浸渍法制备了Ni2P/TiO2-Al2O3催化剂,并用X射线衍射(XRD)、N2吸附比表面积(BET)测定、热重-差热分析(TG-DTA)、X射线光电子能谱(XPS)等技术对催化剂的结构和性质进行了表征.催化剂加氢脱硫(HDS)和脱氮(HDN)活性评价在实验室固定床连续反应装置上,以噻吩和吡啶为模型反应物进行.考察了不同载体、Ni2P负载量、标称Ni/P摩尔比、催化剂焙烧温度对Ni2P/TiO2-Al2O3催化剂上同时进行的噻吩加氢脱硫和吡啶加氢脱氮性能的影响.结果表明,TiO2含量为80%(w)的TiO2-Al2O3复合氧化物为载体,Ni2P负载量为30.0%(w),标称Ni/P摩尔比为1/2,催化剂焙烧温度为500℃时,Ni2P/TiO2-Al2O3催化剂加氢脱硫脱氮活性最高.在360℃,3.0MPa,氢油比800(V/V),液时体积空速1.5h-1的条件下,噻吩HDS和吡啶HDN转化率分别为61.32%和64.43%.     

钼钒氧簇二聚体[Ni(enMe)_2]_4{[Ni(enMe)_2][Ni(enMe)_2(H_2O)]_2[Mo_8~(Ⅵ)V_6~(Ⅳ)O_(38)(V~ⅤO_4)]_2}·8H_2O的合成与结构表征(英文)

在水热条件下合成了一例新型的多金属氧酸盐二聚物,[Ni(enMe)2]4{[Ni(enMe)2][Ni(enMe)2(H2O)]2[Mo8ⅥV6ⅣO38(VⅤO4)]2}.8H2O(1)(enMe=1,2-丙二胺),利用元素分析、红外光谱分析、粉末X射线衍射、热重分析和单晶X射线衍射表征了其结构。结果表明,化合物(1)属于单斜晶系,P2(1)/n空间群.晶胞参数为a=1.9685(4)nm,b=1.3549(3)nm,c=2.7039(5)nm,α=90°,β=93.94(3)°,γ=90°,V=7.195(2)nm3,Z=4,Dc=2.390g/cm3,Mr=2588.4,μ=3.195mm-1,F(000)=5012,最终R1=0.0743,wR2=0.1861.与此同时,(1)是第一个具有二帽-Keggin型钼钒氧簇的二聚体,它由过渡金属部分[Ni(enMe)2(H2O)]22+连接形成{[Ni(enMe)2][Ni(enMe)2(H2O)]2[Mo8ⅥV6ⅣO38(VⅤO4)]2}8-二聚阴离子.     

TiO2-Al2O3载体的制备及Ni2P/TiO2-Al2O3催化剂上的同时加氢脱硫和加氢脱氮反应

 以溶胶-凝胶法制备的 TiO2-Al2O3 复合氧化物为载体, 采用浸渍法制备了 Ni2P/TiO2-Al2O3 催化剂, 并用 X 射线衍射、N2 吸附脱附、红外和 X 射线光电子能谱等技术对催化剂进行了表征, 考察了载体中 TiO2 含量、焙烧温度及其制备方法对 Ni2P/TiO2-Al2O3 催化剂上同时进行噻吩加氢脱硫和吡啶加氢脱氮反应的影响. 结果表明, 以 Ni/P 摩尔比为 1/2 的前驱体制备的催化剂表面仅出现 Ni2P 物相; 当载体中 TiO2 的含量为 80%, 焙烧温度为 550 oC 时, Ni2P/TiO2-Al2O3 催化剂上加氢脱硫和加氢脱氮的活性最高. 在 360 oC, 3.0 MPa, 氢/油体积比 500, 液时体积空速 2.0 h?1 的条件下, 噻吩和吡啶转化率分别为 61.3%和 64.4%.     

三种纳米片组装的α-4CaO·5B_2O_3·7H_2O纳米结构的可控制备、表征及其阻燃性能

以Ca(NO3)2·4H2O和Na2B4O7·10H2O为原料,水和乙醇为混合溶剂,在水热120℃条件下,可控制备了α-4CaO·5B2O3·7H2O纳米片以及由纳米片组装成的球形和蚕蛹状α-4CaO·5B2O3·7H2O纳米结构,通过X射线粉晶衍射(XRD)、X射线能谱分析(EDS)、红外光谱(FT-IR)和扫描电子显微镜(SEM)等手段对产物进行了表征.考察了反应温度、反应时间、溶剂及表面活性剂等条件对硼酸钙α-4CaO·5B2O3·7H2O形貌及尺寸的影响,提出了α-4CaO·5B2O3·7H2O纳米结构的可能形成机理.通过热分析法研究了三种不同形貌硼酸钙α-4CaO·5B2O3·7H2O样品的阻燃性能,结果表明其阻燃性能比非纳米样品好.     

炭包覆氧化铝负载镍催化剂的制备和表征及其催化加氢性能

以炭包覆A12O3(CCA)为载体,采用等体积浸渍法制备了17%Ni/CCA催化剂,采用热重-差示量热扫描、扫描电镜、X射线光电子能谱、N2物理吸附、H2程序升温还原和X射线衍射等手段对样品进行了表征,并用于粗1,4-丁二醇加氢反应中.结果表明,炭的引入显著改变了Al2O3的表面性质、负载Ni的存在形态以及金属.载体间...     

新颖四核镍夹心的杂化锗钨酸盐的合成、结构与表征

在水热条件下合成了一个新颖的夹心结构四核镍有机-无机杂化锗钨酸盐[Ni(dien)(H2O)3]2·[Ni(Hdien)2]{[Ni(dien)]2Ni4(H2O)2(GeW9O34)2}·10H2O(1), 利用X射线单晶衍射确定了其结构, 并通过红外光谱、热重、X射线粉末衍射、X射线能谱和元素分析对其进行了表征. 其晶体属三斜晶系, P1, a=1.1937(3) nm, b=1.4323(3) nm, c=1.6394(4) nm, α=93.424(2)°, β=96.058(3)°, γ=109.758(4)°, V=2.6094(1) nm3,Z=1. X射线单晶衍射结果表明, 化合物1是由夹心构型的多阴离子通过镍-二乙烯三胺配阳离子连接形成的一维线性结构.     

ACo_2O_4/HZSM-5催化剂上N_2O的直接分解

分别采用柠檬酸络合燃烧法和低温络合浸渍法制备尖晶石型复合金属氧化物催化剂ACo2O4(A=Mg,Ni,Zn)和分子筛负载尖晶石型复合金属氧化物催化剂ACo2O4/HZSM-5(A=Mg,Fe,Ni,Cu,Zn,Zr,La).采用X射线衍射(XRD)、氨程序升温脱附(NH3-TPD)、扫描电子显微镜(SEM)和X射线能谱(EDS)等手段对催化剂进行表征,并在固定床微型反应器中评价其催化分解N2O活性.实验结果表明,A位离子种类影响ACo2O4/HZSM-5催化剂活性,以Ni、Fe、Zr或La为A位离子时,催化剂的活性较好,N2O分解温度低.ACo2O4/HZSM-5催化剂的活性高于ACo2O4尖晶石型复合氧化物,一方面是ACo2O4在分子筛HZSM-5载体上高度分散,使其以超细颗粒形态存在,另一方面ACo2O4/HZSM-5催化剂具有适宜的酸性,可提高催化剂的活性.     

载体对合成气制甲烷镍基催化剂性能的影响

考察了A12O3-1,Al2O3-2和SiO2负载的Ni基催化剂上合成气制甲烷的反应活性和稳定性.结果表明,Ni/Al2O3-2和Ni/SiO2催化剂表现出较高的催化活性和稳定性,而Ni/Al2O3-1催化剂稳定性极差.采用X射线衍射、透射电镜、程序升温还原、N2吸附-脱附和热重分析等技术对催化剂进行了表征.结果显示,...     

二维钨-钒簇聚物[Cu(en)_2]_2·[W_(4.5)~ⅥW_2~ⅤV~ⅤV_(9.5)~ⅣO_(44){Cu(en)_2(H_2O)}_2]·3H_2O的合成与表征

采用水热法合成了一个钨-钒簇聚物[Cu(en)2]2[WⅥ4.5WⅤ2VⅤVⅣ9.5O4 4{Cu(en)2(H2O)}2]·3H2O(1,en=乙二胺),并通过X射线单晶衍射、元素分析、傅里叶变换红外光谱、X射线粉末衍射、热重分析、价键计算、X射线光电子能谱、电子顺磁共振和磁性分析对其结构和性能进行了表征.结果表明,化合物1是以双支撑的四帽Keggin结构[WⅥ4.5WⅤ2VⅣ9.5O4 0(VⅤO4){Cu(en)2(H2O)}2]4-钨-钒簇合物阴离子为基本结构单元,与4个[Cu(en)2]2+配合物阳离子以共价键和弱键相连接形成二维层状结构,相邻层又通过氢键连接成三维超分子网络.研究了化合物1的磁性及光催化降解罗丹明B的活性.     

预还原催化剂LaNiO3, La4Ni3O10, La3Ni2O7和La2NiO4 催化分解CH4制碳纳米管 的研究

通过预还原的LaNiO3,La4Ni3O10,La3Ni2O7和La2NiO4催化分解CH4可以制备大量高度石墨化的碳纳米管。还原前后的催化剂的结构和组分通过X射线衍射(XRD)测定。所制得的碳纳米管由扫描电镜(TEM)、X射线光电子能谱(XPS)表征。碳纳米管在空气在的热氧化性由热重实验(TG)测定。实验结果表明不同催化剂前驱中的La/Ni比会影响碳纳米管的管径分布和石墨化程度。La/Ni比越小,碳纳米管的管径越大,石墨化程度越高。     

NiCo2O4纳米线对 H2O2电还原的催化性能

以无模板生长法制备了泡沫镍载NiCo2O4纳米线正极材料, XRD和SEM表征结果表明, 所得材料为NiCo2O4纳米线, 以循环伏安法和计时电流法研究了泡沫镍载NiCo2O4纳米线对H2O2电还原的催化性能. 结果显示, 在0.4 mol/L H2O2 和 3.0 mol/L NaOH 溶液中, 当电压为-0.4 V(vs. Ag/AgCl)时, 循环伏安的电流密度达到125 mA/cm2; 当电压为-0.2, -0.3和 -0.4 V 时, 在30 min 的测试时间内, 计时电流密度几乎均为一常数, 表明以泡沫镍载NiCo2O4纳米线为催化剂电还原H2O2具有很高的活性和很好的稳定性.     

Effect of CeO2 on the catalytic performance of Ni/Al2O3 for autothermal reforming of methane

The effect of promoter Ce on the catalytic performance of Ni/Al2O3 catalyst for autothermal reforming of methane to hydrogen was investigated. The catalysts were characterized by X-ray diffraction （XRD）, temperature-programmed reduction （TPR）, and X-ray photoelectron spectroscopy （XPS）. The results indicated that the catalytic performance of the catalysts was improved with the addition of Ce. Ni/Ce30Al70Oδ showed the highest CH4 conversion in operation temperatures ranging from 650 ℃ to 850 ℃. At the same time, the decrease in H2/CO ratio with increasing reaction temperature was consistent with the fact that water-gas shift reaction was thermodynamically unfavorable at higher temperatures. The XRD result indicated that adding Ce to Ni/Al2O3 catalyst prevented the formation of NiAl2O4 and facilitated the formation of NiO. The formation of NiO increased the number of active sites, resulting in higher activity. Comparing the TPR profiles of Ni/Ce30Al70Oδ with Ni/Al2O3, it could be clearly observed that with the addition of Ce, the total reduction peak areas in the middle and low temperatures increased. It was most probably that the addition of Ce inhibited the stronger interaction between Ni and Al2O3 to form the phase of NiAl2O4, and favored the formation of the strong interaction between NiO species and CeO2. Therefore, the addition of Ce to the Ni/Al2O3 catalyst increased the active surface that promoted the activity of the catalyst.     

纳米结晶体Ni0.5Zn0.5Fe2O4对高氯酸铵热行为及分解反应动力学的影响

采用差示扫描量热法(DSC)、热重和微分热重(TG-DTG)及固相原位反应池/快速扫描傅立叶变换红外联用技术(hyphenated in situ thermolysis/RSFTIR)研究了纳米结晶体Ni_0.5Zn_0.5Fe₂O₄与高氯酸铵(AP)组成的混合物的热行为和分解反应动力学。结果表明：Ni_0.5Zn_0.5Fe₂O₄使得AP的低、高温分解放热峰温分别提前17.44 K和27.74 K,并使得对应的分解热分别增加3.7 J·g^-1和193.7 J·g^-1。Ni_0.5Zn_0.5Fe₂O₄并不影响AP的晶转温度和晶转热。Ni_0.5Zn_0.5Fe₂O₄使得AP的TG曲线出现3个阶段,并使得后2个失重阶段的初始和终止温度都有所提前。凝聚相分解产物分析表明Ni_0.5Zn_0.5Fe₂O₄加速了凝聚相AP的分解及氨气的释放。含Ni_0.5Zn_0.5Fe₂O₄的AP的高温分解反应的动力学参数E_a=238.88 kJ·mol^-1,A=1018.59 s^-1,动力学方程可表示为dα/dt=10^18.99(1-α)[-ln(1-α)]^3/5e^-2.87×104T。始点温度(T_e)和峰顶温度(T_p)计算得出AP的热爆炸临界温度值分别为:574.83 K和595.41 K。分解反应的活化熵(ΔS^≠)、活化焓(ΔH^≠)和活化能(ΔG^≠)分别为:109.61 J·mol^-1·K^-1、236.49 kJ·mol^-1及172.58 kJ·mol^-1。     

柠檬酸对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吸附比表面积测定、H2程序升温氢还原(H2-TPR)、程序升温氧化(TPO)、X射线光电子能谱(XPS)技术对催化剂的结构和性质进行了表征,考察了CA/Ni摩尔比对在Ni2P/TiO2-Al2O3催化剂上进行的二苯并噻吩(DBT)加氢脱硫(HDS)性能的影响.结果表明:适量的CA可以丰富催化剂的孔道,提高催化剂的比表面积.当n(CA)/n(Ni)=2:1时,催化剂的比表面积达到126.75m2·g-1,与不加CA时相比,提高了57.05m2·g-1.调节n(CA)/n(Ni)能够改善活性相的分布,改变活性相的种类;引入CA使Ni和P前驱体的还原温度明显降低,促进活性相Ni2P的生成,一定程度上能够抑制催化剂表面炭的形成和沉积,提高其稳定性.n(CA)/n(Ni)=2:1时,催化剂具有最好的加氢脱硫活性,在360°C,3.0MPa,氢油比为500(V/V),液时体积空速为2.0h-1的条件下,二苯并噻吩转化率为99.5%,可将模拟油中硫含量由2%(w)降低到0.01%(w).     

Formation of CO(x)-free H2 and cup-stacked carbon nanotubes over nano-Ni dispersed single wall carbon nanohorns

Transitional metals (M) were dispersed on single-wall carbon nanohorns (M/SWCNHs, M = Fe, Co, Ni, Cu) by simple thermal treatment of the deposited metal nitrate without H(2) reduction. Nanometallic Ni particles on SWCNH were evidenced by high-resolution transmission electron microscopic observation and X-ray photoelectron spectroscopy. The nano-Ni dispersed on SWCNH showed the highest CH(4) decomposition activity; the activity of used transitional metals decreases in the order Ni ? Co > Fe ? Cu. On the other hand, the reaction rate over Ni/SWCNH was much larger than that over Ni/Al(2)O(3), and the former provided CO(x)-free H(2) and cup-stacked carbon nanotubes, while Ni/Al(2)O(3) produced CO(x) in addition to H(2). SWCNH was superior to Al(2)O(3) as the catalyst support of Ni for the CH(4) decomposition reaction.     

合成温度对全梯度正极材料LiNi0.7Co0.15O2的结构和电化学性能影响

通过控制结晶法和浓度梯度进料的方式制备了Ni、Co和Mn三元素组分含量呈全梯度分布的类球形Ni_0.7Co_0.15Mn_0.15（OH）₂前驱体,与LiOH·H₂O均匀混合并焙烧后获得LiNi_0.7Co_0.15O₂正极材料,系统研究了不同焙烧温度对材料Ni、Co和Mn三元素扩散情况、晶体结构及电化学性能的影响规律。通过能谱仪（EDXS）分析不同焙烧温度下材料颗粒中Ni、Co、Mn三元素的扩散程度。研究结果表明,在800℃下焙烧得到的正极材料梯度分布特征明显且电化学性能最佳,首次放电比容量为186.1 mAh·g^-1（2.8~4.3 V,0.2C）,2C大倍率充放电条件下循环200次后容量保持率为90.1%。这种材料兼具高比容量及良好的循环稳定性,可以用作下一代高能量密度锂离子电池正极材料。     

Effect of Various Synthesis methods on the Electrochemical Properties of LiNi1/3Co1/3Mn1/3O2

Layered LiNi1/3Co1/3Mn1/3O2 has the isostructure of α-NaFeO2 and shows high rate capacity with stable cycleability. Furthermore, the thermal behavior of this material is milder than that of lithium nickel oxide and lithium cobalt oxide. In addition, it is expected to be stable at elevated temperatures. Therefore LiNi1/3Co1/3Mn1/3O2 may be the most promising cathode materials of lithium-ion secondary battery.In this research, LiNi1/3Co1/3Mn1/3O2 was prepared by solid-state reaction, sol-gel method and mixed hydroxide method. The influences of synthesis method on the physical and electrochemical properties of LiNi1/3Co1/3Mn1/3O2 were characterized by means of X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), charge/discharge cycling cyclic voltammetry and differential scanning calorimetry (DSC). XPS studies show that the predominant oxidation states of Ni, Co and Mn in the LiNi1/3Co1/3Mn1/3O2 compound are 2+, 3+ and 4+. From the voltage profile and cyclic voltammetry, the redox processes occurring at ～3.8V and ～4.5V are assigned to the Ni2+/Ni3+ and Co3+/Co4+ couples, respectively. Different preparation methods result in the difference in morphology (shape, particle size and specific surface area) and electrochemical behaviors. A sample prepared by solid-state reaction has the worst electrochemical performance among these three methods. Sample synthesized by mixed hydroxide method displays the better rate capacity than that prepared by sol-gel method, while the capacity retention of sample prepared by sol-gel method is superior to that synthesized by mixed hydroxide method.     

Ni-V-O催化剂的合成、表征及其催化性能

制备了Ni3V2O8, Ni2V2O7, NiV2O6催化剂, 进行了XRD, BET, H2-TPR, XPS和电导等表征, 并测试了这三种结构催化剂对丙烷氧化脱氢制丙烯反应的催化性能, 分析了影响催化性能的因素. 实验结果表明, 当丙烷的转化率为10%时, 在p-型半导体Ni3V2O8和Ni2V2O7催化剂上丙烯的选择性为69.13%和70.21%, 而在n-型半导体NiV2O6上, 丙烯的选择性为64.41%, 表明p-型半导体Ni3V2O8和Ni2V2O7的催化性能优于n-型半导体NiV2O6的催化性能. XPS实验结果表明, 这可能与p-型半导体正钒酸镍(Ni3V2O8)和焦钒酸镍(Ni2V2O7)催化剂表面含较多O-氧物种和V4+有关.