Ce_xTi_(1-x)O_2 Mixed Oxides Supported CuO Catalyst for NO Reduction by CO

Ce x Ti 1- x O 2 mixed oxides of different mole ratios ( x =0, 0.1, 0.2～0.9, 1.0) were prepared by co precipitation of TiCl 4 with Ce(NO 3) 3 and then loaded with different amounts of CuO. The effects of CuO on NO+CO reaction were investigated, and the structure and reductive properties of various CuO/Ce x Ti 1- x O 2 were characterized by the methodologies of BET, TPR and XRD. The results show that different Ce/Ti mole ratios and calcination temperatures induce changes of structure and reductive properties of the Ce x Ti 1- x O 2 mixed oxides. When x =0.1～0.5, amorphous CeTi 2O 6 phase mainly forms at 650 ℃ compared to the formation of CeTi 2O 6 which crystallizes at 800 ℃. When x >0.6, some TiO 2 enters the CeO 2 lattice and a CeO 2 TiO 2 solid solution is formed. The activity of 6%CuO/Ce x Ti 1- x O 2 calcined at 650 ℃ is largely affected by the x values, which is the highest when x =0.3, 0.4 and 0.9. The NO conversion reaches 70% at a reaction temperature of 150 ℃. By comparison, the x values have little effect on the activity of 6%CuO/Ce x Ti 1- x O 2 calcined at 800 ℃ . There are strong interactions between CuO and CeTi 2O 6, i.e., formation of the CeTi 2O 6 phase shifts the CuO reduction peak temperature from 380 to 200 ℃, and CuO, in turn, shifts the CeTi 2O 6 reduction peak temperature from 600 to 300 ℃.

Preparation of defect free ceramic/Ti composite membranes by surface modification and in situ oxidation

Al2O3 ceramic powder was applied to modify the large pores defects on the surface of the porous metal Ti support,in situ oxidation method was a convenient method to prepare defect free ceramic/Ti composite membranes on this basis.In situ oxidation conditions experimental results show that the best condition for preparing the TiO2-Al2O3/Ti composite membrane is under 800°C for 2 h,and the microstructure and pore sizes of the TiO2-Al2O3/Ti composite membranes are affected obviously.The thickness and composition of the TiO2/Ti composite membranes are determined by SEM and XRD completely.The pore size distribution of the composite membrane is measured by bubble pressure method,the most probable aperture is about 3.12μm,while the average pore size of defect free TiO2-Al2O3/Ti is about 3.23μm.After ultrasonic treatment,the slight weight change of membranes reveals no observable change,which indicates that TiO2-Al2O3/Ti composite membranes maintain a good stability.

Surface topography of La-Ti composite oxide nanocrystallines examined with atomic force microscope

By means of atomic force microscope, the surface pattern, particle size distribution, and specific surface area of La Ti composite oxide were studied. The compound particle surface appears as a smooth sheet, the even size of the compound ranges from 19.85 nm to 25.38 nm. The particle seems smooth, which erects at a height from 4.69 nm to 5.88 nm.The surface area ranges from 58.90 nm 2 to 1 238.04 nm 2. The La Ti composite oxide nanocrystallines enjoy a narrow and even particle size distribution and accumulate closely.

Preparation of La-Ti Composite Oxide Nanocrystal and Examination of Their Surface Topography with Atomic Force Microscope

With sol-gel method, nanometer La-Ti composite oxide was successfully prepared at a low temperature (750～800C) using polyethylene glycol as dispersant. By means of atomic force microscope, the surface pattern, particle size distribution, and specific surface area were studied. The compound particle surface appears as a smooth sheet, the mean size of the compound is 25.38 nm. On the specific surface, the particle erects at a height of 4.69 nm. The surface area is 58.90 nm2. The La-Ti composite oxide nanocrystal prefers to narrow and even particle size distribution and the homogeneity of surface topography.

Preparation of magnetic Fe3O4@Cu/Ce microspheres for efficient catalytic oxidation co-adsorption of arsenic(Ⅲ)

Magnetic Fe3 O4@Cu/Ce microspheres were successfully prepared by one-step solvothermal approach and further utilized to remediate toxic arsenic(As(Ⅲ)) pollution. The effects of Cu/Ce elements co-doping on the crystal structure, catalytic oxidation and adsorption behaviors of magnetic microspheres were researched systematically. The results showed that with the aid of Cu/Ce elements, the grain size reduced, lattice defects increased, and the oxygen vacancies and surface hydroxyl groups were improved. Therefore, Cu/Ce elements endowed magnetic Fe3 O4@Cu/Ce microspheres with excellent As(III) removal performance, whose maximum adsorption capacity reached 139.19 mg/g. The adsorption mechanism mainly involved catalytic oxidant co-adsorption. This research developed a feasible strategy for the preparation of high efficiency magnetic adsorbent to enhance the removal of As(Ⅲ).

Enhanced selective catalytic reduction of NO with NH3 via porous micro-spherical aggregates of Mn–Ce–Fe–Ti mixed oxide nanoparticles

We rationally designed a high performance denitration(De-NOx) catalyst based on a micrometer-sized spherical Mn–Ce–Fe–Ti(CP-SD)catalyst for selective catalytic reduction(SCR). This was prepared by a co-precipitation and spray drying(CP-SD) method. The catalyst was systematically characterized, and its morphological structure and surface properties were identified. Compare with conventional Mn–Ce–Fe–Ti(CP) catalysts, the Mn–Ce–Fe–Ti(CP-SD) catalyst had superior surface-adsorbed oxygen leading to enhanced 'fast NH3-SCR' reaction. The asobtained Mn–Ce–Fe–Ti(CP-SD) catalyst offered excellent NO conversion and N2 selectivity of 100.0% and 84.8% at 250℃, respectively, with a gas hourly space velocity(GHSV) of 40,000 h-1. The porous micro-spherical structure provides a larger surface area and more active sites to adsorb and activate the reaction gases. In addition, the uniform distribution and strong interaction of manganese, iron, cerium, and titanium oxide species improved H2O and SO2 resistance. The results showed that the Mn–Ce–Fe–Ti(CP-SD) catalyst could be used prospectively as a denitration(De-NOx) catalyst.

Textures and mineral compositions of the Xinjie layered intrusion,SW China:Implications for the origin of magnetite and fractionation process of Fe-Ti-rich basaltic magmas

The Xinjie layered intrusion in the Panxi region,SW China,hosts both Fe-Ti oxide and platinum-group element（PGE） sulfide mineralization.The intrusion can be divided,from the base upward,into UnitsⅠ,ⅡandⅢ,in terms of mineral assemblages.UnitsⅠandⅡare mainly composed of wehrlite and clino-pyroxenite, whereas UnitⅢis mainly composed of gabbro.PGE sulfide-rich layers mainly occur in Unit I, whereas thick Fe-Ti oxide-rich layers mainly occur in UnitⅢ.An ilmenite-rich layer occurs at the top of UnitⅠ.Fe-Ti oxides include magnetite and ilmenite.Small amounts of cumulus and intercumulus magnetite occur in UnitsⅠandⅡ.Cumulus magnetite grains are commonly euhedral and enclosed within olivine and clinopyroxene.They have high Cr2O3 contents ranging from 6.02 to 22.5 wt.%,indicating that they are likely an early crystallized phase from magmas.Intercumulus magnetite that usually displays ilmenite exsolution occupies the interstices between cumulus olivine crystals and coexists with interstitial clinopyroxene and plagioclase.Intercumulus magnetite has Cr2O3 ranging from 1.65 to 6.18 wt.%, lower than cumulus magnetite.The intercumulus magnetite may have crystallized from the trapped liquid.Large amounts of magnetite in UnitⅢcontains Cr2O3（＆lt;0.28 wt.%） much lower than magnetite in UnitsⅠandⅡ.The magnetite in UnitⅢis proposed to be accumulated from a Fe-Ti-rich melt.The Fe-Ti-rich melt is estimated to contain 35.9 wt.%of SiO2,26.9 wt.%of FeOt,8.2 wt.%of TiO2,13.2 wt.%of CaO, 8.3 wt.%of MgO,5.5 wt.%of Al2O3 and 1.0 wt.%of P2O5.The composition is comparable with the Fe-rich melts in the Skaergaard and Sept Iles intrusions.Paired non-reactive microstructures,granophyre pockets and ilmenite-rich intergrowths,are representative of Si-rich melt and Fe-Ti-rich melt,and are the direct evidence for the existence of an immiscible Fe-Ti-rich melt that formed from an evolved ferro-basaltic magma.

A STEEL MATRIX WEAR RESISTANT COMPOSITE REINFORCED BY IN-SITU GRANULAR EUTECTICS

A new steel matrix wear resistant composite reinforced by in situ granular eutectics can be obtained by modifying with a Si-Ce-Ti compound in the steel melt. The result indicates that the in situ granular eutectic is a pseudo-eutectic of austenite and (Fe,Mn)3C, which is formed between austenite dendrites during solidification due to the segregation of C and Mn impelled by modifying elements. The quantity of in situ granular eutectic reaches up to 8%-12% and its grain size is in the range from 10um to 20um. The austenite steel matrix wear resistant composite reinforced by in situ granular eutectic (abbreviated AGE composite) and austenite-bainite steel mains wear resistant composite reinforced by in situ granular eutectic (abbreviated ABGE composite) are obtained in the as-cast state and by air hardening, respectively. The wear resistance of the AGE and ABGE composites can be more greatly increased than that of their matrix steels under low and medium impact working condition.

非晶Ce-Ti氧化物用于NH_3选择性催化还原NO的原位红外研究

采用原位红外光谱研究了在具有短程有序Ce–O–Ti结构的非晶Ce-Ti氧化物上NH3选择性催化还原(SCR)NOx反应.在反应条件下,催化剂表面主要被NH3吸附物种覆盖,而检测不到NOx吸附物种.经测定,NO的反应级数为0.5–0.6,表明Langmuir-Hinshelwood机理和Eley-Rideal机理同时存在.可能的机理是NH3吸附物种和弱吸附的NOx反应,生成NHyNO3(y=0–4)活性中间物种,并通过GAUSSIAN计算和原位红外结果证实了它们的存在.Ce–O–Ti结构中Ce与Ti之间表现出原子尺度的相互作用,所以在SCR反应的活性温度窗口下,催化剂的氧化还原活性提高.

Ca及Ce低合金化对TiC_p/AZ91镁基复合材料组织性能的影响

将加入Ca及Ce元素低合金化和采用XD法制备的Ti Cp/Al预制块相结合,并进行半固态搅拌的方法制备Ti Cp/AZ91镁合金复合材料,对其显微组织和力学性能进行分析测试。结果表明:加入0.3wt%Ca、0.3wt%Ce后,AZ91镁合金与Ti Cp/AZ91镁基复合材料的组织明显细化,β-Mg17Al12相减少。少量Ca、Ce的加入有利于熔炼时镁合金的熔体保护,可减少细小Ti C粒子的团聚,提高抗拉强度及伸长率。

Ce-Cu/Ti-Al-O_x催化氧化CO的性能研究

采用挤出成型法制备系列铜铈负载钛铝氧化物(Ce-Cu/Ti-Al-Ox)催化剂,研究Ce-Cu/Ti-Al-Ox催化氧化一氧化碳(CO)的性能,并对催化剂进行表征。结果表明:三氧化二铝(Al2O3)的掺入抑制了二氧化钛(TiO2)的颗粒长大,不仅增大了催化剂的比表面积,同时提高了铜铈负载二氧化钛(Ce-Cu/TiO2)催化剂的缺陷浓度,有利于催化剂表面反应气体的吸附以及催化反应的进行,因此适量添加Al2O3能明显提升Ce-Cu/TiO2催化剂的低温催化氧化活性,拓宽其活性温度窗口,添加20%(wt,质量分数)Al2O3制得的Ce-Cu/Ti-Al-Ox催化剂具有对催化氧化CO的最好催化活性,在140℃条件下,活性达到了98%,170℃以上活性达到了100%。

Ti/Ce复合氧化物的制备及改性研究

采用燃烧法制备单体氧化物,异相成核沉淀法制备Ti/Ce复合氧化物并对其进行改性。采用XRD、IR、UV-vis、SEM对Ti/Ce复合氧化物进行了表征。对制备的样品进行改性研究,考察了改性剂类型、改性温度、酸度、改性剂用量等条件对改性效果的影响,得出改性工艺的最佳条件。对于CeO2/TiO2:改性剂选择钛酸酯偶联剂,温度45℃,时间60min,pH值为7,改性剂用量为5%(质量分数)。TiO2/CeO2:改性剂选择钛酸酯偶联剂,温度55℃,时间60min,pH值为6,改性剂用量为5%。改性后可增强样品在基体中的可溶性,扩大其适用范围。

溶胶-凝胶法制备超细Ce-Ti复合粉体的研究

采用溶胶一凝胶法制备了Ce-Ti复合超细粉体，主要研究了溶胶一凝胶法制备过程中溶胶一凝胶形成的条件及不同焙烧温度对超细粉体粒径的影响。结果表明，C2H5OH与H2O摩尔比在0.5～2.0时能形成稳定的凝胶；采用真空干燥能形成松散的结构，不易团聚，真空干燥温度60℃，真空干燥压力5kPa左右，真空干燥时间大于24h；超细Ce-Ti复合粉体的平均粒径随干凝胶焙烧温度的升高而增加，在600℃下焙烧1h，能得到较好的效果，粒径可达5.9nm。

基于Pt-Ce-Ti催化剂的烧结烟气CO氧化性能研究

为减少烧结烟气中CO排放,采用浸渍法制备了一系列Pt-Ce-Ti催化剂,并在模拟的烧结烟气中测试了催化剂的CO催化氧化性能。首先,通过改变TiO_(2)载体上Pt的质量分数,研究了Pt质量分数与催化剂活性的关系;其次,通过共浸渍掺杂和载体的形式,研究了CeO_(2)对催化剂活性的影响;然后,研究了催化剂的抗SO_(2)性能;最后,通过XRD,BET和XPS等表征手段研究了催化剂活性差异的机理。研究结果表明:催化剂活性随着Pt质量分数提高而提高;在Pt质量分数为0.1%的基础上以CeO_(2)为载体或微量掺杂,可以提高催化剂的活性,Pt_(0.1%) /TiO_(2)、Pt_(0.1%) /CeO_(2)和Pt_(0.1%) Ce_(0.1%)/TiO_(2)催化剂在120℃活性分别为6.80%,84.84%和99.99%;Pt_(0.1%) Ce_(0.1%)/TiO_(2)的抗硫能力突出,在SO_(2)体积分数为0.003%的混合气中,CO平均氧化率为87.0%。催化剂中Pt质量分数越高,CO吸附和反应位点越多,催化剂活性越高。加入CeO_(2)会增加催化剂表面吸附氧数量,增强催化氧化过程供氧能力,提高催化剂的活性。TiO_(2)可以促使水分子解离成羟基,促进CO催化氧化过程,并与SO_(2)形成竞争吸附作用,提高催化剂抗SO_(2)性能。

Microstructure and abrasive wear behaviour of anodizing composite films containing Si C nanoparticles on Ti6Al4V alloy

Anodized composite films containing Si C nanoparticles were synthesized on Ti6Al4 V alloy by anodic oxidation procedure in C4O6H4Na2 electrolyte. Scanning electron microscopy(SEM), energy dispersive spectroscopy(EDS) and X-ray photoelectron spectroscopy(XPS) were employed to characterize the morphology and composition of the films fabricated in the electrolytes with and without addition of Si C nanoparticles. Results show that Si C particles can be successfully incorporated into the oxide film during the anodizing process and preferentially concentrate within internal cavities and micro-cracks. The ball-on-disk sliding tests indicate that Si C-containing oxide films register much lower wear rate than the oxide films without Si C under dry sliding condition. Si C particles are likely to melt and then are oxidized by frictional heat during sliding tests. Potentiodynamic polarization behavior reveals that the anodized alloy with Si C nanoparticles results in a reduction in passive current density to about 1.54×10-8 A/cm2, which is more than two times lower than that of the Ti O2 film(3.73×10-8 A/cm2). The synthesized composite film has good anti-wear and anti-corrosion properties and the growth mechanism of nanocomposite film is also discussed.

Mn-Fe-Ce-O催化剂对助燃脱硝性能的影响

采用改进的柠檬酸络合法制备了Mn-Fe-Ce-O复合氧化物,采用XRD,H_(2)-TPR,XPS,SEM,EDS等方法分析了试样的结构与物性,并对其氧化和催化CO还原NO的性能进行了评价。实验结果表明,Mn-Fe-Ce-O复合氧化物中主要为Mn_(3)O_(4)和CeO_(2)物相,Fe和Ce的加入可增大复合氧化物的比表面积,且表面元素分布均匀,无明显集聚状态,加入Ce后复合氧化物颗粒变得细小,Mn^(3+)+Mn^(4+)含量和表面吸附氧含量增大,H_(2)-TPR还原峰向低温区偏移。Mn_(9)Fe_(1)O_(z)具有良好的氧化CO能力,400℃下CO转化率为99.56%,Mn-Fe-Ce-O复合氧化物催化CO还原NO的活性高于Mn-Fe-O复合氧化物,其中,(Mn_(9)Fe_(1))_(7)Ce_(3)O_(z)活性最高,在350℃下NO转化率为85.75%。

Ce改性Ni/MnO_(x)催化剂用于甲烷干重整的研究

采用氧化还原沉淀法制备了系列xCe(100-x)MnO_(x)(简记为xC(100-x)M,x分别为0、10%、30%、50%、80%、100%)复合氧化物,通过浸渍法负载Ni制备Ni/xC(100-x)M系列催化剂。以CH_(4)干重整反应制合成气为模型反应,研究Ce与Mn质量比对Ni/CeMnO_(x)催化剂活性的影响。结果表明,在Ni/MnO_(x)催化剂中引入Ce助剂,提高了催化剂的比表面积和表面碱性位点数量,改善了催化剂的还原能力。在系列Ni/CeMnO_(x)催化剂中,Ce与Mn质量比对反应活性有着显著的影响,Ce质量分数的增加有利于提高CH_(4)和CO_(2)转化率,在反应温度为700℃和V(CH_(4))/V(CO_(2))=1∶1的条件下,Ni80C20M催化剂的CH_(4)和CO_(2)转化率相对较高,CH_(4)转化率为73.90%,CO_(2)转化率为79.38%。

Preparation and characteristics of nano-crystalline Cu-Ce-Zr-O composite oxides via a green route: supercritical anti-solvent process

The nano-crystalline Cu-Ce-Zr-O composite oxides were successfully prepared by the supercritical anti-solvent （SAS） process. The physicochemical properties and catalytic performances were investigated by X-ray diffraction （XRD）, Raman spectroscopy, H2 temperature-programmed reduction （H2 -TPR）, oxygen storage capacity （OSC） measurement and catalytic activity evaluation. It was found that Cu2＋ ions incorporated into CeO2 -ZrO2 lattice to form Cu-Ce-Zr-O solid solution associated with the formation of oxygen vacancies. The Cu-Ce-Zr-O catalysts prepared via the SAS process with the Cu content 2.63 mol.% showed the highest OSC index of 636.9 μmol/g. Compared with the samples prepared by impregnation method, Cu doping using SAS process could improve the dispersion of Cu2＋ in the composite oxide, enhance the interaction between Cu2＋ and CeO2-ZrO2 , improve the reducibility of catalyst, and thus improve the OSC performance and increase the catalytic activity for CO oxidation at low temperature.

稀土Ce掺杂SnSb复合涂层电极的实验研究

采用涂刷热分解氧化法,把无机盐SnCl4.5H2O、SbCl3和Ce(NO3)3.6H2O以一定的配比溶解在有机溶剂异丙醇中制备涂层液,以钛板为基体,制备多组分的涂层电极。考察了不同掺杂量下制备的电极对生活污水的处理效果,并对稀土Ce掺杂SnSb涂层进行了SEM表征,结果表明,在热处理温度为500℃、稀土掺杂量(原子质量比)为Sn∶Sb∶Ce=100∶10∶1的电极降解效果最好;稀土Ce的掺杂有利于锡锑金属氧化物涂层电极的电化学性能的提高。

Ti-6Al-4V微弧氧化陶瓷膜微观结构与组成研究

在NaAlO_2,Na_3PO_4混合电解液中,利用微弧氧化(MAO)技术在Ti-6Al-4V合金表面制备了氧化物陶瓷膜。用扫描电镜(SEM),能量散射谱仪(EDS),X射线光电子能谱仪(XPS)对氧化物陶瓷膜的微观结构与组成进行了分析。结果表明：微弧氧化陶瓷膜表面和界面均呈现多孔结构,表面孔径大小差别较大,界面孔径大小差别较小,氧化膜界面处较规则地平行排列着一些长丘陵状突起；氧化膜疏松层与致密层无明显界限,氧化膜与基底以犬牙交错状结合。EDS分析结果表明,氧化膜表面、界面均由Ti,Al,P,V元素组成,Al元素易在表面富集,P元素易在界面富集。XPS分析结果表明,氧化膜表面、界面存在TiO_2,Al_2O_3,TiAl_2O_5等相,P元素均以P0_4^(3-)形式存在；氧化膜界面处存在V_2O_5相,而表面并不存在V元素。