Ag-Pd bimetallic nanoparticles were prepared directly in ultrathin TiO(2)-gel films by a stepwise ion-exchange/reduction approach. Ion-exchange sites were created in ultrathin films using Mg(2+) ions as template. Ag(+) ion was then incorporated by ion exchange, and converted into metallic nanoparticles by low-temperature H(2) plasma, regenerating ion-exchange sites. The same procedure was then carried out for Pd(2+) ion, producing Pd-on-Ag bimetallic nanoparticles, as TEM observation and plasmon resonance absorption indicate. By contrast, reversed metal incorporation procedure appeared to give a mixture of individual Ag and Pd nanoparticles, as confirmed by TEM, absorption spectroscopy and X-ray photoelectron spectroscopy. For hydrogenation of methyl acrylate, the catalytic activity of the Pd-on-Ag nanoparticle is 367 times as large as that of commercial Pd black and 1.6 times as large as that of Pd monometallic nanoparticle. The outstanding catalytic activity was explicable by the large fraction of the surface-exposed Pd atoms. The formation process of the bimetallic nanoparticle and their general morphological feature are discussed.

Palladium nanoparticles covered with liquid-crystal molecules were prepared by UV irradiation of an alcohol solution of palladium(II) acetate in the presence of liquid-crystal molecules. The prepared Pd nanoparticles have an average diameter of 2.5 nm. A twisted nematic (TN) liquid-crystal device (LCD) was fabricated by doping with Pd nanoparticles covered with another kind of nematic liquid-crystal molecules. In this device the sign of the dielectric anisotropy (Δε) of the liquid-crystal molecules, which cover Pd nanoparticles, is opposite to that of nematic liquid-crystal molecules, which work as the host of the device (Δε>0). The TN-LCD cell fabricated in this research exhibits a frequency modulation response to an applied alternative voltage wave form.

A novel class of hybrid organic thermoelectric materials is demonstrated for the first time for constructing flexible thermoelectric devices on polyimide substrates with high output power by using nanotechnology instead of conducting polymers such as poly(3,4-ethylenedioxythiophene). The hybrid organic thermoelectric materials are composed of nanoparticles of a polymer complex, carbon nanotubes, and poly(vinyl chloride), and show high performance (dimensionless thermoelectric figure-of-merit, ZT ≈ 0.3, based on the thermal conductivity through the film).

2000255 (1 of 9) Pd-based nanosheet materials have emerged as efficient catalysts for monobasic and polyhydric alcohol oxidation reactions. However, most reported synthetic methods of Pd-based nanosheets (NSs) are nonuniversal and surfactant-involved, leading to residue-covered surfaces with drastically damaged electrocatalytic properties. Herein, a universal, surfactant-free, simple one-pot route is developed for the precise synthesis of a kind of novel self-standing Pd-M (M = Ag, Pb, Au, Ga, Cu, Pt, etc.) NSs with tremella-like superstructures are assembled using ultrathin two-dimensional (2D) NSs. Benefiting from the universal surfactant-free methods, the obtained Pd-M NSs exhibit clean surfaces and stable three-dimensional (3D) self-standing structures that overcome the difficulty of normal close packing and overlapping 2D NSs. The Pd-M (M = Ag, Pb, and Au) NSs with tremella-like structures all show excellent ethanol oxidation reaction (EOR) and ethylene glycol oxidation reaction (EGOR) properties. In particular, with the optimal superstructure, better electronic effect, and promoted toxicity tolerance, the EOR/EGOR mass activities of Pd 7 Ag NSs, Pd 7 Pb NSs, and Pd 7 Au NSs are 8.2/7.3, 7.2/5.7, and 5.3/4.4 times higher than that of commercial Pd/C catalysts. This advanced 3D construction also endows Pd-M NSs with more favorable stability than Pd/C. This study may be extended to Pd-M (M = other metals) NSs and open up more opportunities for broad catalytic applications.

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The design of nanocatalysts by controlling pore size and particle characteristics is crucial to enhance the selectivity and activity of the catalysts. Thus, we have successfully demonstrated the synthesis of binary PdPb alloy nanocubes (PdPb NCs) by controlling pore size and particle characteristics. In addition, the as-obtained binary PdPb NCs exhibited superior electrocatalytic activity of 4.06 A mg and 16.8 mA cm toward ethylene glycol oxidation reaction and 2.22 A mg and 9.2 mA cm toward glycerol oxidation reaction when compared to the commercial Pd/C. These astonishing characteristics are attributed to the attractive nanocube structures as well as the large number of exposed active areas. Furthermore, the bifunctional effects originated from Pd and Pb interactions help to display high endurance with less activity decay after 500 cycles, showing a great potential in fuel cell applications.