CuO/ZnO/Y2O3/γ-Al2O3双功能催化剂上二甲醚水蒸气重整制氢

将沉积-沉淀法制备的CuO/ZnO/Y2O3催化剂同γ-Al2O3进行机械混合, 制备了CuO/ZnO/Y2O3/γ-Al2O3双功能催化剂, 用于二甲醚水蒸气重整制氢反应, 实验结果表明其活性、稳定性等均优于常用的CuO/ZnO/Al2O3/γ-Al2O3催化剂. 结合N2吸附-脱附(BET)、N2O化学吸附(N2O chemisorption)、NH3程序升温脱附(NH3-TPD)、X射线衍射(XRD)、H2程序升温还原(H2-TPR)等表征手段研究了两种催化剂在表面酸性及微观结构上的差异, 发现CuO/ZnO/Y2O3催化剂具有相对较高的铜分散度, 铜晶粒更加细小化, 并且具有高温稳定性的Y2O3可能起到隔离铜的作用, 在一定程度上防止了铜晶粒的团聚, 从而改善了重整组分的性能, 提高了双功能催化剂的重整制氢活性及稳定性.     

一维纳米Co_3O_4,Ag/Co_3O_4及CuO/Co_3O_4的合成与电催化性能(英文)

采用水热合成法制备了Co3O4及复合Ag/Co3O4、CuO/Co3O4一维纳米产品。用XRD,FE-SEM和TEM手段对产品进行了表征。采用循环伏安法研究了合成产品修饰的玻碳电极在碱性溶液中对对硝基苯酚的电催化还原性能。与裸玻碳电极相比,1mmol·L-1的对硝基苯酚在用Co3O4、特别是CuO/Co3O4修饰的玻碳电极上还原的峰电流明显增大,用Ag/Co3O4(Ag/Co原子比分别为1∶5和2∶5)修饰的玻碳电极催化还原对硝基苯酚时,尽管还原峰电流增大不是太大,但其峰电位明显降低(分别降低0.265和0.371V)。     

Al掺杂量对正极材料LiNi_(1/3)Co_(2/3-x)Al_xO_2结构和电化学性能的影响

以共沉淀法合成的前驱体Ni1/3Co2/3-xAlx(OH)2与低共熔锂盐0.38LiOH·H2O-0.62LiNO3制备了锂离子电池正极材料LiNi1/3Co2/3-xAlxO2(x=1/12,1/6,1/3,1/2,7/12).采用X射线衍射(XRD)、扫描电镜(SEM)和电化学性能测试对其结构、形貌和电化学性质进行表征.结果表明,LiNi1/3Co2/3-xAlxO2在1/12≤x≤1/3范围内可以保持单一的六方层状α-NaFeO2结构,当Al掺杂量(x)高于1/3时,会出现杂相.其中,LiNi1/3Co1/3Al1/3O2结晶程度最高,阳离子混排效应最小,并且颗粒小而均匀,振实密度可以达到2.88g·cm-3,首次放电容量为151.5mAh·g-1,循环50次后放电容量保持在91.4%,在1C和2C倍率下放电容量仍可达到133.7和120.9mAh·g-1.     

Survey of the quasi-ternary system La0.8Sr0.2MnO3–La0.8Sr0.2CoO3–La0.8Sr0.2FeO3

An overview on the variation of the thermal expansion, the electrical conductivity as well as non-stoichiometry of the oxide content as a function of composition within the quasi-ternary system La_0.8Sr_0.2MnO_3−δ–La_0.8Sr_0.2CoO_3−δ–La_0.8Sr_0.2FeO_3−δ in air is presented. The various powders were synthesized under identical conditions. The DC electrical conductivity values of the compositions at 800 °C in air vary in a wide range from 15 to 1338 S cm⁻¹. The magnitude of electrical conductivity of the perovskites is mainly determined by the percentage of cobalt in the compositions. A similar behaviour was observed for the measured thermal expansion coefficients between room temperature and 1000 °C in air, increasing from 10.9 to 19.4 × 10⁻⁶ K⁻¹ as a function of cobalt content. Changes in the oxygen stoichiometry of the materials were characterized by temperature-programmed oxidation measurements.     

Electrochemical performance of a nano SnO2-modified LiNi1/3Co1/3Mn1/3O2 cathode material

The nano SnO₂-modified LiNi_1/3Co_1/3Mn_1/3O₂ was successfully prepared by a carrier transfer method. The pristine and modified samples were characterized with various techniques such as XRD, SEM, XPS and EDS. The results showed that the SnO₂ particles did not enter the crystal structure of LiNi1/3Co1/ 3Mn1/3O₂, many nano SnO₂ particles were uniformly covered on the surface of LiNi_1/3Co_1/3Mn_1/3O₂ and the modified thin layer could inhibit the dissolution of transition metal oxides. The electrochemical tests indicated that the existence of nano SnO₂ could improve the discharge capacity and rate capability owing to the decreased interfacial polarization. The cycling stability was remarkably improved at room temperature and 55 ℃. The XRD patterns of the fresh NCM electrode and after 50 cycles proved that the structural change of NCM was not so effective on the capacity fade.     

煤灰/K_2CO_3/Fe_2O_3对脱矿无烟煤燃点与燃烧速率的影响(英文)

考察了煤灰/K2CO3/Fe2O3及其之间的相互作用对酸洗无烟煤燃点和燃烧速率的影响。不同温度下制备的煤灰显示了不一样的性质(如化学组成、颜色和形貌)。脱矿无烟煤(负载和非负载催化剂)的燃烧反应性测试在热重分析仪(TGDTG)中完成,结果表明,煤灰本身对酸洗无烟煤的燃点几乎没有影响,而高温下制备的煤灰能够明显提高酸洗无烟煤的燃烧速率。当煤灰和K2CO3或者Fe2O3的混合物加入酸洗无烟煤中作为燃烧催化剂时,可以看出与单独使用K2CO3或Fe2O3相比,煤灰的加入明显导致酸洗煤的燃烧速率下降,而对其燃点影响不大。同样,K2CO3和Fe2O3之间的相互作用也能够对酸洗无烟煤的燃烧速率产生负面影响。     

凹凸棒土/g-C3N4-Pt/聚苯胺复合材料的制备及其可见光催化性能

石墨氮化碳(g?C₃N₄)是一种窄带隙的n型半导体材料,具有可见光降解有机污染物能力;凹凸棒土(ATP)具有很强的表面活性和吸附能力,可作为催化剂的载体。我们以g?C₃N₄和ATP杂化材料(ATP/g?C₃N₄)为基础,通过简单的化学还原法将纳米Pt颗粒沉积到ATP/g?C₃N₄表面,随后利用纳米金属Pt颗粒催化苯胺无电聚合,促使聚苯胺(PANI)在ATP/g?C₃N₄表面或孔道中原位生成,获得ATP/g?C₃N₄?Pt/PANI复合材料。以阴离子染料甲基橙(MO)为模型体系,考察了复合材料的可见光催化性能。研究表明,共轭结构的PANI和g?C₃N₄在复合材料中保持完好,说明其具有良好的兼容性。由于多组分材料之间的协同效应,使得ATP/g?C₃N₄?Pt/PANI纳米复合材料具有卓越的光催化性能。可见光光照80 min后,对20 mg·L^-1 MO溶液的降解率达96.3%,而且循环5次后,其降解率仍保持在93.5%。     

γ-Al2O3对SCR脱硝催化剂V2O5-WO3/TiO2的改性研究

采用溶胶凝胶法制备了不同γ-Al₂O₃含量的钛铝复合载体,以此为载体采用浸渍法负载V₂O₅和WO₃制备了一系列催化剂。采用X射线衍射(XRD)、比表面积测定(BET)、程序升温还原(H₂-TPR)、高分辨率透射电子显微镜(HRTEM)等表征技术对催化剂表面形态进行分析,同时在模拟氨气选择性催化还原NO(NH₃-SCR)的反应条件下,对催化剂的脱硝反应活性和SO₂抗中毒进行考察。结果发现,TiO₂和γ-Al₂O₃之间的协同作用使得V₂O₅-WO₃/TiO₂-γ-Al₂O₃催化剂的脱硝效率及活性窗口明显优于单一载体制备的催化剂,表现出了良好的热稳定性和抗SO₂毒化能力,特别是V₂O₅-WO₃/TiO₂-15% γ-Al₂O₃在310~460 ℃,NO的转化率均在80%以上,反应窗口最宽。各种表征结果表明,TiO₂-γ-Al₂O₃复合载体中γ-Al₂O₃高度分散在TiO₂上,复合载体具有较大的比表面积,同时具有较强的还原能力。     

The effect of Al substitution on the reactivity of delithiated LiNi1/3Mn1/3Co(1/3−z)AlzO2 with non-aqueous electrolyte

The high temperature reactions between 1 M LiPF₆ EC:DEC and Al-doped LiNi_1/3Mn_1/3Co_(1/3−z)Al_zO₂ charged to 4.3 V were studied by accelerating rate calorimetry (ARC) and compared with those of charged LiNi_1/3Mn_1/3Co_1/3O₂ and LiMn₂O₄. Al substitution for Co in LiNi_1/3Mn_1/3Co_1/3O₂ improves the thermal stability. Materials with z > 0.06 are less reactive with electrolyte than spinel LiMn₂O₄ at all temperatures studied. The maximum self-heating rate (SHR) attained and the specific capacity decrease as the Al content increases. There is a range of compositions near z = 0.1 that show excellent promise as materials which are both safer than and more energy dense than spinel LiMn₂O₄.     

Thermal studies on the electrical conductivity of some (CnH2n+1NH3)2CuCl4 (n = 1,2) and (CH2)(CH3)2CuCl4 complexes

The electrical conductivities of the compounds (CH₃NH₃)₂CuCl₄, (C₂H₅NH₃)₂CuCl₄ and (CH₂)₂(NH₃)₂CuCl₄ were measured in the temperature range which includes their structural phase transition. The values of the activation energies as calculated from the Arrhenius equation are reported. Confirmation of the phase transition temperatures is carried out using differential thermal analysis in the same temperature range as the conductivity measurements.     

Mesoporous MnSiO3@Fe3O4@C Nanoparticle as pH-responsive T1-T2* Dual-modal Magnetic Resonance Imaging Contrast Agent for Tumor Diagnosis

Mesoporous structured MnSiO₃@Fe₃O₄@C nanoparticles (NPs) were prepared via a facile and efficient strategy, with negligible cytotoxicity and minor side efforts. The asprepared MnSiO₃@Fe₃O₄@C NPs hold great potential in serving as pH-responsive T₁-T₂^* dual-modal magnetic resonance (MR) imaging contrast agents. The released Mn²⁺ shortened T₁ relaxation time, meanwhile the superparamagnetic Fe₃O₄ enhanced T₂ contrast imaging. The release rate of Mn ions reaches 31.66% under the condition of pH=5.0, which is similar to tumor microenvironment and organelles. Cytotoxicity assays show that MnSiO₃@Fe₃O₄@C NPs have minor toxicity, even at high concentrations. After intravenous injection of MnSiO₃@Fe₃O₄@C NPs, a rapid contrast enhancement in tumors was achieved with a significant enhancement of 132% after 24 h of the administration. Moreover, a significant decreasement of 53.8% was witnessed in T₂ MR imaging signal. It demonstrated that MnSiO₃@Fe₃O₄@C NPs can act as both positive and negative MR imaging contrast agents. Besides, owing to the pH-responsive degradation of mesoporous MnSiO₃, MnSiO₃@Fe₃O₄@C NPs can also be used as potential drug systems for cancer theranostics.     

Phase separation, cation ordering and nano-structural complexities in Nd2/3−xLi3xTiO3 with x=0.14

Transmission electron microscopy (TEM) investigations on Nd_2/3−xLi_3xTiO₃ with x=0.14 reveal a rich variety of structural features in the samples prepared under different conditions, such as superstructures, anti-phase domains, and nano-chessboard structures. Our careful analysis shows that these structural phenomena can be fundamentally understood as the combination of structural effects of (Nd, Li)-ordering along the 〈001〉_p direction and the spinodal decomposition along the 〈100〉_p/〈010〉_p direction. The coexistence of phase separation and cation ordering can lead to visible nano-structural complexities in many crystals, as the typical results, the regular lamella structure, nano-chessboard structures and anti-phase boundaries have been extensively studied.     

Solvothermal synthesis and luminescence properties of monodisperse Gd2O3:Eu and Gd2O3:Eu@SiO2 nanospheres

A series of uniform, monodispersed Gd(OH)³:Eu³⁺ nanospheres less than 100 nm were successfully synthesized with iron ions as catalyst and DMF as solvent under the solvothermal condition. Cetyltrimethyl ammonium bromide (CTAB) and Polyvinylpyrrolidone (PVP) were performed as co-surfactant during this facile procedure should be changed as A series of uniform, monodisperse Gd(OH)³:Eu³⁺ nanospheres less than 100 nm in diameter were successfully synthesized with solvothermal method. Iron ion was used as catalyst and Dimethylformamide (DMF) as solvent, Cetyltrimethyl Ammonium Bromide (CTAB) and Polyvinylpyrrolidone (PVP) were performed as surfactants. Further calcination process was applied to prepare Gd₂O₃:Eu³⁺ nanoshpheres during this facile procedure.     

VOx/SiO2-Al2O3催化剂催化苯羟基化制苯酚

以硅溶胶为硅源、偏铝酸钠为铝源及环己胺合成SiO2-Al2O3复合氧化物,并采用水热合成法合成了VOx/SiO2-Al2O3催化剂。采用XRD、SEM、TEM、XPS、NH3-TPD、N2物理吸/脱附等手段对此催化剂和复合氧化物微观结构进行表征分析。由表征结果可知钒活性中心能够高分散于此复合氧化物表面,VOx/SiO2-Al2O3催化剂呈现层片积雪状;当钒的含量为4%时,催化剂中V4+含量最大且总酸量契合于此反应所需要的催化酸环境。探究了4%VOx/SiO2-Al2O3催化剂对苯羟基化制苯酚反应的催化性能,结果表明：基于高分散活性中心、V4+含量最大及载体酸性环境等优点而表现出良好的催化性能,苯转化率为48.1%,苯酚选择性为99.6%。     

Extraction of U/VI/ and U/IV/ with some 1-phenyl-3-methyl-4-acylated-pyrazolone-5 compounds

A series of novel chelating reagents 1-phenyl-3-Methyl-4-p-Nitro-Benzoyl-Pyrazolone-5 /PMNBP/, 1-Phenyl-3-Methyl-4-o-Chlor-Benzoyl-Pyrazolone-5 /PMCBP/, 1-Phenyl-3-Methyl-4-Acyl-Pyrazolone-5 /PMAP/ have been synthesized. The extraction of U/VI/ and U/IV/ from hydrochloric acid in chloroform with these reagents as well as 1-Phenyl-3-Methyl-4-Benzoyl-Pyrazolone-5 /PMBP/ has been studied. The influence of the concentration of the reagents in organic phase, on the distrubtion ratio /D/, has been measured. The coordination of the compounds has been determined with the slope method, and the equilibrium constants k_ex, were measured.     

Pt/γ-Al2O3/CexZr1-xO2催化剂低温催化燃烧去除饮食油烟

以CexZr1-xO2固溶体做载体, 制备了系列Pt/γ-Al2O3/CexZr1-xO2催化剂(x=1, 0.75, 0.5, 0.25, 0). 应用Brunauer-Emmet-Teller (BET)比表面积分析、X射线衍射(XRD)和H2程序升温还原(H2-TPR)等手段对催化剂进行相关表征, 并系统研究了催化剂在饮食油烟催化燃烧中的催化活性. BET结果表明催化剂的比表面积随Ce/Zr摩尔比的减小而减小. XRD结果表明贵金属Pt很好地分散在氧化铝和CexZr1-xO2固溶体上. H2-TPR结果发现催化剂Pt/γ-Al2O3/Ce0.5Zr0.5O2的还原峰面积最大且氧离子的流动性最好. 催化活性研究结果表明Pt负载在CexZr1-xO2固溶体上有利于油烟的催化燃烧, 降低了反应温度. 随着CexZr1-xO2固溶体中Ce/Zr摩尔比的变化, 催化剂的活性顺序为Pt/γ-Al2O3/Ce0.5Zr0.5O2>Pt/γ-Al2O3/Ce0.25Zr0.75O2>Pt/γ-Al2O3/Ce0.75Zr0.25O2>Pt/γ-Al2O3/CeO2>Pt/γ-Al2O3/ZrO2.     

Li2O-Al2O3-GeO2-P2O5微晶玻璃的微观结构和离子电导率

采用传统熔体冷却法制备了Li3-xAl2-xGex(PO4)3(x=1.1~1.9)体系玻璃,并通过热处理工艺获得了高电导率的微晶玻璃。通过XRD、TEM和交流阻抗等测试方法,研究了该系微晶玻璃的物相组成、微观形貌和锂离子电导率。结果表明:该系统微晶玻璃析出导电主晶相为LiGe2(PO4)3,杂质相为AlPO4和GeO2。当x=1.5时,由于导电主晶相LiGe2(PO4)3晶粒充分长大、分布均匀,所制备微晶玻璃的室温锂离子电导率最高(5.72×10-4 S.cm-1),可以满足全固态锂离子电池对电解质高室温电导率的要求。     

Co-Mo/SiO2-Al2O3润滑油加氢处理催化剂的制备

以Pluronic P₁₂₃作结构导向剂,采用Al （NO₃）₃-NaAlO₂双水解法合成氧化铝,在成胶过程中加入正硅酸乙酯,制备硅质量分数分别为5%、10%、15%的SiO₂-Al₂O₃载体,并通过共浸渍法制备出Co-Mo/SiO₂-Al₂O₃润滑油加氢处理催化剂。通过XRD、N₂吸附-脱附、Py-FTIR、NH₃-TPD、H₂-TPR、TEM和XRF等手段对载体及催化剂的性质进行表征。结果表明,硅质量分数为10%的SiO₂-Al₂O₃具有优良的孔结构、较多的中强酸以及部分有序的介孔结构。以此为载体制备的Co-Mo/10% SiO₂-Al₂O₃催化剂中,MoS₂颗粒均匀地分散在载体上,具有更多的B酸性位和Ⅱ型CoMoS活性相。以减二线蜡油为原料油的固定床活性评价结果表明,生成油中主要组分为链烷烃与环烷烃;尤其Co-Mo/10% SiO₂-Al₂O₃催化剂具有优良的加氢性能,在15 MPa、380℃、氢油比为1000、空速为0.6 h^-1的反应条件下,其HDS和HDN数值均超过99%,产品中S含量小于10 μg/g,N含量小于2 μg/g,可以满足后续异构脱蜡等对原料的要求。     

Fe2O3与TiF3添加剂对LiBH4-MgH2复合氢化物体系的协同催化作用

通过球磨方法制备出2LiBH4-MgH2,2LiBH4-MgH2-10%Fe2O3,2LiBH4-MgH2-10%TiF3,2LiBH4-MgH2-5%Fe2O3-5%TiF3和2LiBH4-MgH2-10%Fe2O3-10%TiF35个复合氢化物体系,用热重(TG)、差示扫描量热(DSC)、X射线衍射(XRD)、傅里叶变换红外光谱(FTIR)和压力-组成-温度仪(PCT)等对所制备体系进行表征.结果表明,Fe2O3和TiF3的掺杂均能够有效地改善2LiBH4-MgH2复合体系的放氢性能,尤其是两者共掺杂的2LiBH4-MgH2-10%Fe2O3-10%TiF3体系,初始放氢温度为110℃,总放氢量达到约9.6%.对2LiBH4-MgH2-5%Fe2O3-5%TiF3体系的PCT表征结果表明,在400℃时,10 min内放氢量达到了8.6%,放氢热力学和放氢动力学均优于单一相的掺杂,体现了两相掺杂的协同催化作用.     

Co3O4/CeO2 CO氧化的原位红外光谱研究

采用沉淀氧化法制备了Co₃O₄/CeO₂催化剂。分别在干、湿条件下进行了一氧化碳氧化反应研究。运用FT-IR表征手段,在钴铈复合氧化物上进行了CO吸附及CO/O₂共吸附研究。结果表明,与纯的Co₃O₄样品相比,Co₃O₄/CeO₂具有明显的抗湿气能力。Co₃O₄/CeO₂催化剂在进行CO氧化时,表面形成了类碳酸盐物种。当环境温度低于453 K时,催化剂上类碳酸盐的生成与形成类碳酸盐物种后受热分解存在着动态平衡。当环境温度高于493 K,催化剂上生成的类碳酸盐物全部受热分解。氧化铈的加入提高了催化剂的抗湿气性能。较小粒径的Co₃O₄与CeO₂产生的强相互作用可使CeO₂向Co₃O₄提供氧,因而间接提供了CO氧化需要的氧。