Large Scale Photochemical Synthesis of M@TiO_(2) Nanocomposites (M = Ag, Pd, Au, Pt) and Their Optical Properties, CO Oxidation Performance, and Antibacterial Effect

Well-dispersed M@TiO_(2)(M=Ag,Pd,Au,Pt)nanocomposite particles with a diameter of 200-400 nm can be synthesized on a large scale by a clean photochemical route which does not require any additives using spherical rutile nanoparticles as a support.The sizes of Pt,Au,and Pd nanoparticles formed on the surface of TiO_(2) particles are about 1 nm,5 nm,and 5 nm,respectively,and the diameter of Ag nanoparticles is in the range 2-20 nm.Moreover,the noble metal nanoparticles have good dispersity on the particles of the TiO_(2) support,resulting in excellent catalytic activities.Complete conversion in catalytic CO oxidation is reached at temperatures as low as 333 and 363 K,respectively,for Pt@TiO_(2) and Pd@TiO_(2) catalysts.In addition,the antibacterial effects of the as-synthesized TiO_(2) nanoparticles,silver nanoparticles,and Au@TiO_(2) and Ag@TiO_(2) nanocomposites have been tested against Gram-negative Escherichia coli(E.coli)bacteria.The results demonstrate that the presence of the TiO_(2) matrix enhances the antibacterial effect of silver nanoparticles,and the growth of E.coli can be completely inhibited even if the concentration of Ag in Ag@TiO_(2) nanocomposite is very low(10μg/mL).

Magnetic Field-Induced Solvothermal Synthesis of One-Dimensional Assemblies of Ni Co Alloy Microstructures

One-dimensional magnetic Ni Co alloy microwires with different microstructures and differently shaped building blocks including spherical particles,multilayer stacked alloy plates,and alloy flowers,have been synthesized by an external magnetic field-assisted solvothermal reaction of mixtures of cobalt(II)chloride and nickel(II)chloride in 1,2-propanediol with different NaOH concentrations.By adjusting the experimental parameters,such as precursor concentration and Ni/Co ratio,Ni Co alloy chains with uniform diameters in the range 500 nm to 1.3μm and lengths ranging from several micrometers to hundreds of micrometers can be obtained.A mechanism of formation of the one-dimensional assemblies of magnetic NiCo microparticles in a weak external magnetic fi eld is proposed.