基于3-吡啶-3-苯甲酸构筑的配合物[M(3,3-PBC)_2(H_2O)_2](M=Zn,Ni,Co)的合成、表征和性能研究

在水热条件下,采用3-吡啶-3-苯甲酸(3,3-HPBC)和过渡金属盐合成了3种新型配合物[M(3,3-PBC)2(H2O)2](M=Zn,Ni,Co)。通过元素分析、化学分析、红外光谱、热重分析等方法对配合物组成进行了分析和表征。此外,研究了Zn(3,3-PBC)2(H2O)2配合物的荧光性质。     

多孔LaMO_3(M=Co,Fe)纳米催化剂的制备及一氧化碳催化氧化性能

钙钛矿型氧化物催化剂(ABO3)具有廉价易得、高热稳定性、催化活性高的优点,在催化一氧化碳(CO)低温脱除领域具有重要的理论研究意义和实际应用价值。本研究中,以聚苯乙烯(PS)微球、碳微球为模板,硝酸镧、硝酸钴、硝酸铁为金属源,柠檬酸为络合剂,通过溶胶-凝胶法制备了多孔LaCoO_3和多孔LaFeO_3催化剂。采用X射线衍射、热重-差热、扫描电镜、透射电镜和氮气吸附-脱附等手段对所得样品进行了系统表征分析。结果表明:所制备的催化剂具有高纯度和高热稳定性。加入11.12g PS微球所制备的多孔LaCoO_3催化剂平均颗粒粒径为13nm,加入0.5g碳微球制备的多孔LaFeO_3催化剂平均粒径为19nm,且具有介孔和微孔分级孔结构。催化性能测试结果表明:在同等条件下对CO转化率达到50%时,多孔LaCoO_3和多孔LaFeO_3使得催化温度分别降低了43℃和32℃;CO完全转化温度则分别降低了90℃和60℃。     

20%BaCO_3/La_(0.8)Sr_(0.2)MO_3(M=Fe,Co,Mn)催化分解NO的研究

通过NO程序升温吸附脱附(NO-TPD)分析测试手段,研究了20%BaCO3/La0.8Sr0.2MO3(M=Fe、Co、Mn)催化分解NO的机理,解释La0.8Sr0.2MO3(M=Fe、Co、Mn)与BaCO3简单混合后催化分解NO的性能提升的原因。     

两个组成相近,结构不同的配位聚合物(Cudpt)3[Fe(CN)6](ClO4)2·3H2O和(Cudpt)3[Fe(CN)6](ClO4)2·4H2O的合成和结构(dpt:二丙烯三胺)

(Cudpt)(ClO4)2和K4[Fe(CN)6]反应得到配位聚合物(Cudpt)3[Fe(CN)6](ClO4)2*3H2O(1),在相似条件下用Cu(ClO4)2,dpt和K4[Fe(CN)6]反应得到配位聚合物(Cudpt3[Fe(CN)6](ClO4)2*4H2O(2),解析了它们的晶体结构.这两个化合物有相同的I.R.和UV-Vis谱,但它们的结构却有显著的不同,前者是一维链状结构,后者则是二维网状结构.     

Luminol-K_3[Fe(CN)_6]化学发光法测定汽油中的铅

根据铅(Ⅱ)催化K3[Fe(CN)6]氧化Luminol产生化学发光的事实,结合流动注射分析技术,建立了一种发光定量测定铅的新方法。实验结果表明,该方法对Pb(Ⅱ)的检出限为3.8×10-7mol/L,工作曲线线性范围为1.0×10-6～1.0×10-4mol/L,测定浓度为1.0×10-5mol/L,Pb(Ⅱ)的相对标准偏差为3.5%(n=11),通过对汽油样品中铅的检测,结果满意。     

[P_4MP_4]~(n-)(M=Fe,Ru,Os,Co,Rh,Ir;n=1,2)和[P_4MP_4Na]~-(M=Fe,Ru,Os)的结构和稳定性

用密度泛函理论(DFT)研究了标题化合物的电子结构、电离能和稳定性。研究发现,体系的交错型(D4d)结构是稳定的,而重叠型(D4h)异构体则是过渡态。从垂直电离能的计算可知,Fe、Ru和Os的配合物对分子内的库仑排斥力而言是不稳定的,而Co、Rh和Ir的类似物则是稳定的。此外,计算结果表明,钠能作为抗衡离子来抵消分子内的库仑排斥力,使电子不会自发地离去,因为这样可以产生更稳定的结构,即[P4MP4Na]-,从而可以便于实验操作。另外,金属-配体裂解反应能的计算表明这些夹心型配合物都是热稳定的。     

金属有机框架材料M-MOF-74(M=Ni、Co、Fe)的制备及表征

以金属氧化物(Ni O、CoO、Fe O)和2,5-二羟基对苯二甲酸(H4(dhbdc))为原料,采用溶剂热法制备M-MOF-74(M=Ni、Co、Fe)。经X射线衍射(XRD)测定证明产物具有良好晶体结构,通过扫描电镜(SEM)观察产物晶体颗粒大小和外貌,通过比表面积测定仪(BET)测定产物的比表面积,Ni-MOF-74为1114m~2/g,Co-MOF-74为1238m~2/g,Fe-MOF-74为1050m~2/g。     

M-MOF-74(M=Ni,Co,Zn)的制备及其电化学催化合成氨性能

将自然界丰富的氮转化为氨对人类社会发展至关重要。以氮和水为原料的电化学合成氨是极具应用前景的绿色合成过程。采用水热法合成了Ni-, Co-和Zn-MOF-74催化剂,采用XRD、SEM以及XPS等表征了催化剂结构,并在0.1 mol·L-1Na2SO4电解液中研究了它们的电催化合成氨性能。结果表明,在常温常压下,Ni-MOF-74的电催化合成氨性能优于Co-和Zn-MOF-74催化剂,在-0.7 V (vs Ag/Ag Cl)下其氨合成速率和法拉第效率分别高达6.68×10-11mol·s-1·cm-2和23.69%,这归因于Ni-MOF-74不仅颗粒尺寸小且分布均匀,而且具有最多的金属-氧键和最大的电化学比表面。特别是Ni-MOF-74还能有效抑制析氢副反应,从而提高了法拉第效率。     

Li2MnO3·LiMO2(M=Co,Ni)的电子结构与性能

将富锂锰基正极材料Li₂MnO₃·LiMO₂(M=Co,Ni)分为LiMO₂和Li₂MnO₃两部分，基于密度泛函理论第一性原理方法对其分别进行了研究，分析和计算了LiMO₂(M=Co,Ni)的结构和性能及Li₂MnO₃的脱锂过程。结果表明：在LiMO₂(M=Co,Ni)和Li₂MnO₃中锂以离子形式存在，LiNiO₂体系的导电性优于LiCoO₂体系，Li₂MnO₃在脱锂过程中锂离子首先从锂层中脱出，之后从过渡金属层进一步脱锂，其中锂脱出造成的电荷变化主要由O的氧化来补偿。     

类Fenton催化剂M@C(M=Co,Ni)的制备应用及性能对比

以金属有机框架(ZIF-67、Ni-MOF)为前躯体,在氮气下煅烧合成了类Fenton催化剂Co@C、Ni@C,并对催化剂进行了X射线衍射分析,拉曼测试(Raman),扫描电镜(SEM)表征。研究了Co@C和Ni@C催化剂对染料橙黄Ⅱ的降解能力。实验结果表明,碳包覆不同金属的催化剂对橙黄Ⅱ的降解能力存在着明显的差异。在橙黄Ⅱ浓度为20 mg/L,催化剂浓度为25 mg/L,PMS浓度为0.1 g/L,Co@C比Ni@C催化剂有着优异的降解能力。     

稀土配合物[Ln_2(sba)_3(phen)_2(H_2O)_2](Ln=Eu,Tb)合成、表征和性质研究

在乙醇和水的混合溶剂中,利用辛二酸[Suberic acid=H2sba]、邻菲罗啉(Phen)合成了标题化合物,通过化学分析、元素分析、红外光谱、热分解等方法对配合物组成进行了分析和表征,并研究了两种配合物的荧光性质。     

Separation of Xenon and Krypton in the Metal–Organic Frameworks M2(m-dobdc) (M=Co,Ni)

The separation of Xe and Kr from air is challenging owing both to the very low atmospheric concentrations of these gases and the need for their distillation at cryogenic temperatures. Alternatively, separation processes based on adsorption could provide a less energy-intensive route to the isolation of these gases. Here, we demonstrate that the metal–organic frameworks M₂(m-dobdc) (M=Co, Ni; m-dobdc⁴⁻=4,6-dioxido-1,3-benzenedicarboxylate) effectively separate Xe and Kr at ambient temperatures based on the different adsorption enthalpies of each gas at the coordinatively-unsaturated M²⁺ sites in each material. In situ Xe- and Kr-dosed powder X-ray diffraction studies further reveal key differences in the binding of Xe and Kr within the materials. In particular, while both gases adsorb near the framework open metal sites at 200 K, much higher Xe occupancies are observed at these sites relative to Kr, corroborating a stronger interaction of the polarizing M²⁺ cations with Xe. Further, while krypton is only found located above the open metal sites, two additional adsorption sites are observed for xenon, correlating with the stronger adsorption of Xe over Kr in these materials. These results suggest the possible utility of employing M₂(m-dobdc) materials in the adsorptive separation of Xe and Kr.     

Structural and mechanical properties of La0.6Sr0.4M0.1Fe0.9O3-δ (M: Co,Ni and Cu) perovskites

La_0.6Sr_0.4M_0.1Fe_0.9O_3-δ (M: Co, Ni and Cu) perovskite nanostructures were synthesized using low frequency ultrasound assisted synthesis technique and effect of substitution of Fe by Co, Ni and Cu on crystal structure and mechanical properties in La_0.6Sr_0.4FeO_3-δ perovskite was studied. The HRTEM and Rietveld refinement analyses revealed the uniform equi-axial shape of the obtained nanostructures with the existence of La_0.6Sr_0.4M_0.1Fe_0.9O_3−δ with mixed rhombohedral and orthorhombic structures. Substitution by Cu decreases the melting point of La_0.6Sr_0.4FeO_3-δ. The results of mechanical characterizations show that La_0.6Sr_0.4Co_0.1Fe_0.9O_3−δ and La_0.6Sr_0.4Ni_0.1Fe_0.9O_3−δ have ferroelastic behavior and comparable elastic moduli, however, substitution by Ni shows higher hardness and lower fracture toughness than Co in B-site doping.     

Selective oxidation of propane over PMoV?M/α‐Al2O3 (M: Co,Fe, or Ni)

Alumina supported phosphovanodomolybdic acid and alumina supported phosphovanodomolybdic acid‐transition metal ions (M: Fe³⁺, Co²⁺, or Ni²⁺) were prepared by impregnation. The thermal decomposition, in situ at 400°C, of supported catalysts showed the formation of V₂O₅, P₂O₅, MoO₃ and MoO₃, CoMoO₄, (Mo_0.3V_0.7)₂O₅ phases, on the alumina surface, in the presence of H₄PMo₁₁VO₄₀/α‐Al₂O₃ and H₄PMo₁₁VO₄₀? Co/α‐Al₂O₃, respectively. The catalytic activity of alumina‐supported catalysts was evaluated in the reaction of propane oxidation at 380 and 400°C. The addition of transition metal increases the conversion and changes the reaction products distribution. The reaction conditions (temperature and propane/oxygen ratio) have also modified the behaviour of the studied catalysts.     

Nanostructured perovskite oxides – LaMO3 (M=Al,Co, Fe) prepared by co-precipitation method and their ethanol-sensing characteristics

Nanostructured La-based perovskite oxides − LaMO₃ (M=Al, Co, Fe) were synthesized by a new co-precipitation procedure using metal nitrate and carbonate salts as starting materials. X-ray diffraction and energy dispersive X-ray spectroscopic results confirmed the formation of single-phase nanocrystalline perovskite oxides with high purity. Characterizations by scanning/transmission electron microscopy and nitrogen adsorption revealed that LaAlO₃ was produced in the form of rectangular porous nanorods exhibiting much larger surface area and porosity compared with densely aggregated LaCoO₃ particles and loosely clustered LaFeO₃ nanoparticles with cracked-egg morphologies. The materials were characterized for gas sensing towards ethanol at 200–350 °C. From gas-sensing results, the LaAlO₃ sensor displayed n-type gas-sensing behaviors with considerably higher ethanol response than p-type LaFeO₃ and LaCoO₃ sensors, respectively. In particular, the LaAlO₃ sensor exhibited a high response of 16.45–1000 ppm ethanol and excellent ethanol selectivity against NO₂, SO₂, CO and H₂ at 350 °C. The superior gas-sensing performances could be attributed to the effective receptor function, transducer function and utility factor of LaAlO₃ nanorod structures prepared by the co-precipitation method.     

Co-Cu-M(M=Fe,Mn,Ni,Zn,Ce)催化剂催化分解N_2O性能

采用等体积浸渍法制备了添加不同金属助剂的铜钴复合氧化物(Co/Cu质量比为0.6)催化剂,考察了其催化N_2O分解的活性。结果表明,稀土金属Ce以及过渡金属Fe对钴铜催化剂催化N_2O分解的活性有明显的促进作用。通过分析催化剂的X射线衍射(XRD)、比表面积测定(BET)、氢气程序升温还原(H_2-TPR)以及扫描电镜(SEM)等表征结果发现,助剂的添加并没有引起催化剂晶相结构的明显改变,但可以提高钴离子与铜离子的还原能力。尤其是添加Ce和Fe之后还原峰向低温区显著移动,从而提高了钴铜复合氧化物催化剂的活性。     

X-ray phase,structural, dielectric and magnetic studying of BiFe1-х(M1/2Ti1/2)хO3 (M = Co,Ni, Zn, х = 0–0.11) multiferroics

Perovskite-like rhombohedral distorted solid solutions of BiFe_1-х(M_1/2Ti_1/2)_хO₃ (M = Co, Ni, Zn, x = 0–0.11) were obtained by solid-phase synthesis. An indicator of the solid solution formation is the change of unit cells parameters, that corresponds to the ionic radii of mixed cations (M1/2Ti1/2)3+ (M = Co, Ni, Zn. Solid solutions of BiFe_1-х(M_1/2Ti_1/2)_хO₃ (M = Co, Ni), in contrast to BiFe_1-x(Zn_1/2Ti_1/2)_xO₃ demonstrate ferromagnetic hysteresis pels at room temperature. The x growth in the range from 0.01 to 0.11 for the BiFe_1-х(M_1/2Ti_1/2)_хO₃ system leads to, the saturation magnetization M_S and the remanent magnetization M_R increase from ∼0.1 and ∼2.4⋅10⁻³ emu/g to ∼0.4 and ∼0.038 emu/g respectively. In the same time the coercive force H_c decreases from ∼120 to ∼80 Oe. For the BiFe_1-х(Co_1/2Ti_1/2)_хO₃ system, a noticeably higher magnetic properties with a more complex dependence on x are observed. The maximum parameter values are observed at x = 0.04–0.05: M_S = 0.83 and M_R = 0.24 emu/g, H_c = 1.8 kOe. It is suggested that the detected anomalies of Co-containing solid solutions behavior are related to the one-ionic magnetocrystalline anisotropy of Co²⁺ cations. The BiFe_1-х(M_1/2Ti_1/2)_хO₃ (M = Co, Ni) samples demonstrate piezoelectric constant d₃₃ up to 7 pC/N. Due to the set of properties the materials obtained can be classified as high-temperature multiferroics.     

合成方法对NH_4MPO_4·H_2O(M=Mn,Fe,Co,Ni,Cu)颗粒形貌的影响

采用低温固相法与常规液相法合成系列磷酸铵复盐NH4MPO4.H2O(M=Mn,Fe,Co,Ni,Cu),用XRD,FT-IR和SEM对产物进行表征,比较两种合成工艺及产物的颗粒形貌和大小。结果表明,除铜盐为斜方晶系外,其余都为正交晶系。与常规液相法相比,低温固相法不需要使用溶剂,能在低温短时间内合成磷酸铵复盐类化合物,但是需要晶化才能得到良好结晶体,合成的条件较为苛刻,容易有副反应发生,所得产品是片状结构,厚度为纳米尺寸的二维纳米材料,液相反应得到的产物颗粒是层状结构的微米级产品。     

锂离子二次电池新型正极材料LiMPO4(M=Fe、Co、Ni等)的研究进展

综述了锂离子二次电池新型正极材料LIMPO4(M=Fe、Co、Ni、Mn等)的研究进展。重点对该材料的结构、结构与电化学性能的关系、多种阳离子掺杂对材料性能的影响以及多种合成方法进行了较详细的评述,并对该材料的应用前景进行了展望。