Ni– Cu/AC催化剂的制备及其催化氧化甲醇羰基化反应性能研究

以活性炭为载体,采用硝酸镍浸渍液制备负载型镍催化剂Ni/AC,讨论了硝酸镍负载的最佳条件,并引入金属铜对催化剂进行改性。通过比表面积分析仪和扫描电镜SEM分析了催化剂的表面结构,并将两种催化剂应用于甲醇直接氧化羰基化合成醋酸的实验中。结果显示：制备催化剂的最佳条件为硝酸镍浓度1.0 mol/L、浸渍时间1h、温度70℃、硝酸铜浓度0.1mol/L;两种催化剂均具催化活性,双金属镍铜催化剂Ni-Cu/AC活性较高,催化作用下甲醇转化率可达15.7 %。     

Bimetallic nanostructures with magnetic and noble metals and their physicochemical applications

Bimetallic nanomaterials consisting of magnetic metals and noble metals have attracted much interest for their promising potentials in fields such as magnetic sensors, catalysts, optical detection and biomedical applications. Bimetallic nanomaterials synthesized by wet-chemical methods with different architectures including nanoparticles, nanowires or nanotubes and their assemblies are summarized in this review. The particular properties of bimetallic nanomaterials, especially their magnetic, catalytic and optical properties, are presented. The advance in electron microscopy makes it possible to understand the nanostructural materials at much higher level than before, which helps to disclose the relationship between the microstructures and properties qualitatively and quantitatively.     

A novel bimetallic RuFe nanocluster to enable highly efficient oxygen reduction in zinc-air batteries

Zinc-air batteries (ZABs) have the advantages of high energy density and safety but their large-scale application is hindered by sluggish kinetics of four-electron aqueous O₂ redox reactions. Widely used Ruthenium (Ru)-based catalysts possess intrinsic oxygen evolution catalytic activity but suffer from insufficient oxygen reduction reaction (ORR) performance. Herein, to optimize the ORR activity of Ru-based catalyst, an iron (Fe)-coordinated, bimetallic RuFe cluster is constructed and homogeneously dispersed within nitrogen (N)-doped carbon layers (denoted as RuFe@NC). Benefitting from the optimized ORR activity and more active site exposure, the RuFe@NC exhibits superior ORR activity with a half wave potential (E_1/2) of 0.88 ?V higher than that of Pt/C (0.82 ?V). Accordingly, the RuFe@NC-based ZAB outperforms the Pt/C ?+ ?IrO₂-based device, presenting a reduced polarization of 0.7 ?V and an enhanced cycling lifetime of 50 ?h at 10 ?mA ?cm^?2. Moreover, the optimized structural design ultralow Ru loading (0.013 mg_Ru cm^?2) overcomes the cost barriers and demonstrates its high practicality. This bimetallic RuFe nanocluster opens a new way for future design of more efficient and stable catalytic systems.     

Electrocatalytic oxidation of ethanol and ethylene glycol on bimetallic Ni and Ti nanoparticle-modified indium tin oxide electrode in alkaline solution

Bimetallic Ni and Ti nanoparticle-modified indium tin oxide electrode(Ni–TiNPs/ITO) were prepared by a twostep ion implantation method, and their electrocatalytic activity toward the oxidation of ethanol and glycol was evaluated. The ion-implantation method is simple, low-cost and environmental friendly without the use of any binder. The Ni–TiNPs/ITO electrode were characterized by scanning electron microscopy(SEM), atomic force microscopy(AFM) and X-ray photoelectron spectroscopy(XPS). SEM and AFM showed that the nanoparticles on the Ni–TiNPs/ITO electrode had a small range of dispersion(10–20 nm) and high dispersion. Electrochemical performances were measured by cyclic voltammetry(CV) and chronoamperometrics. The Ni–TiNPs/ITO electrode exhibited much higher electrocatalytic activity and stability for ethanol and ethylene glycol oxidation than NiNPs/ITO.     

NiPt hollow nanocatalyst: Green synthesis,size control and electrocatalysis

Nearly monodispersed hollow nanospheres of bimetallic NiPt have been synthesized by a one-pot wet chemical method at room temperature with a precursor Ni nanocompound as a sacrificial template. The size control is carried out via the sacrificial template, from about 35 nm to nearly100 nm in diameter. The shell thickness of the NiPt hollow sphere reaches down to as thin as 2–3 nm slightly larger than a single layer of alloyed NiPt nanocrystallites. The product with the citric acid as surfactant exhibits enhanced oxygen reduction activities compared to a commercial Pt/C catalyst and the hollow nanospheres coated with PVP. It has potential applications in fuel cells, biotechnology and environmental chemistry with the facile synthesis, low cost and excellent electrocatalytic activity.     

Laser synthesized nanoparticle alloys of metals with bulk miscibility gaps

The nanoscale alloying of metals with bulk miscibility gaps, Ag-Pt and Ag-Rh, has been investigated using pulsed laser ablation of solids in solution(PLASiS). The procedure was in two steps. In the first step, the suspensions of monometallic nanoparticles were prepared by ablation of a metal rod submerged in water. In the second step,the monometallic suspensions were mixed and alloying was induced by re-irradiation. For the Ag-Pt system, a surface plasmon resonance was observed in the monometallic silver suspension. The surface plasmon resonance vanished in re-irradiated Ag-Pt suspensions, indicating alloying. Selected Area Electron Diffraction(SAED)analysis showed that the nanoparticles had a fcc structure with a lattice constant intermediate between that of monometallic Ag and Pt nanoparticles. First principles theoretical investigations of the mixing energy of Ag-Pt clusters confirm that mixing is favored at around ～1 nm. The same procedure used for Ag-Pt was followed for Ag-Rh. In this system where the two metals present miscibility gaps even in the liquid phase, no evidence of alloying was observed. Correspondingly, theoretical investigations found that the mixing energy of Ag-Rh clusters did not favor alloying.     

钯团簇掺杂钇原子的密度泛函研究

在相对论有效原子实势近似下,用密度泛函方法(B3LYP/LANL2DZ)计算了二元合金团簇PdnY(n=1-5)可能的几何构型和对应的电子态,得到一系列稳定异构体的结构参数、电子态、能量和谐振频率.用最高占据轨道(HOMO)与最低空轨道(HOMO)之间的能级间隙描述团簇的稳定性,Pd2Y团簇的能级间隙最大,PdY团簇的能级间隙最小.Pd-Y相互作用改变了纯钯团簇的几何构形和稳定性.计算结果对系统研究Pd-Y体系的物理化学性质具有意义.     

Chemical behaviour of Al/Cu nanoparticles in water

Bimetallic Al/Cu nanoparticles with Al/Cu composition 10:90, 20:80, 40:60 were produced by method of simultaneous electrical explosion of metal pairs in the argon atmosphere. Nanopowders containing 20% and 40% (mass) of aluminum interacted with water at 40–70 ℃ and formed composite particles that were porous structures of nanopetal pseudoboehmite with nanosized copper-containing inclusions inside. Aluminum in nanopowder with Al/Cu composition 10:90 did not react with water, as far as it is in the phase of intermetallic compounds Сu Al2and Сu4Al9.Nanocomposite produced can be used as an active component of antibacterial agents.