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Pd@Pt core-shell nanocrystals consisting of well-defined Pd nanocube cores and dendritic Pt shells were prepared by a new facile aqueous one-pot synthetic method. The prepared Pd@Pt nanocrystals exhibited efficient catalytic activity and stability toward methanol electrooxidation, and their catalytic function was highly dependent on their Pt shell thickness due to the different synergism between Pt and Pd.

Cerium and nanocubes: CeO₂-supported Pd-Cu-alloy nanocubes (Pd-Cu NCs/CeO₂) with high content and good dispersion of the Pd-Cu NCs were prepared in high yields by heating a solution containing Pd, Cu, and Ce precursors. The prepared Pd-Cu NCs/CeO₂ have excellent catalytic activity and stability toward formic acid electro-oxidation due to the synergism between the Pd-Cu-alloy catalysts and the CeO₂ support.

Au-Pd alloy nanocrystals (NCs) with a hexoctahedral structure, enclosed exclusively by high-index {541} facets, are prepared via the simultaneous reduction of Au and Pd precursors without added seeds or additional metal ions as structure-regulating agents. Manipulating the NC growth kinetics via control of the relative amount of reductant is the key synthetic lever for controlling the morphology of the Au-Pd NCs. The hexoctahedral Au-Pd NCs exhibit higher catalytic performance toward the electro-oxidation of ethanol than low-index-faceted Au-Pd NCs.

Hex appeal! Cu(2)S-Pd(4)S hybrid nanocrystals with a novel hexagonal nanoplate structure were prepared in high yield by a simple one-pot synthetic method (see figure). Successful synthesis of this unique structure was achieved through a consecutive thermolysis process. The Cu(2)S-Pd(4)S hybrid nanoplates exhibited substantially higher photocatalytic activities than pure Cu(2)S nanoplates.

Fabrication of dendritic Au rod (DAR) structures on Au surfaces via a simple electrodeposition from sulfite-based electrolytes containing Au(I) has been demonstrated. Scanning electron microscopic images show that the DAR structures contain highly faceted star-shaped protrusions in sub-100 nm scale. Electrochemical and X-ray diffraction results reveal that the DAR structures retain high amount of (110) and (100) crystalline domains on their surfaces. The unique morphology and surface orientation of DAR provide high electrocatalytic activities for glucose oxidation and oxygen reduction and efficient surface-enhanced Raman scattering activities.

One-pot synthesis of carbon-supported Pd-Au alloy nanoparticles with well-defined dendritic shape (Pd-Au(den)/C) was achieved by co-reduction of K(2)PdCl(4)/HAuCl(4) mixtures in a molar ratio of 1:1 with hydrazine in the presence of Vulcan XC-72R. The prepared Pd-Au(den)/C exhibited significantly enhanced performance in the electrocatalytic oxidation of ethanol compared with dendritic Pd nanoparticles and a commercial Pd/C catalyst. Pd-Au(den)/C even showed higher durability in electro-oxidation of ethanol than the supported catalyst prepared by the deposition of presynthesized dendritic Pd-Au nanoparticles on the carbon support. The experimental results clearly indicate that enhanced interaction between nanoparticle catalysts and carbon support through the one-pot synthesis protocol can improve the durability of the electrocatalysts.

We investigated AC bias stress instability of indium-gallium-zinc-oxide (IGZO) Thin-film transistors (TFTs). AC bias frequency dependence showed different aspect in IGZO TFTs and a-Si:H TFTs. Influencing factors to AC bias frequency dependence of instability is charge accumulation characteristic under negative bias stress, and detrapping characteristics of shallow trapped charges under positive bias stress.

The stability of oxide-based TFT under bias stress was considerably improved by employing in-Situ thermal pretreatment, which suppresses hydrogen content in the oxide active layer. By suppressing the inflow of hydrogen, easily movable, back interface trapping was reduced and the VTH shift of the oxide TFT was suppressed successfully.