It is a known fact that Pd-based bimetallic nanostructures possess unique properties and excellent catalytic performance. In this work, the Au-Pd alloy and core-shell nanostructures have been prepared by a simple one-pot hydrothermal coreduction route, and their formation process and mechanism are discussed in detail. A reducing capacity-induced controlled reducing mechanism is proposed for the formation process of Au-Pd bimetallic nanostructures. CTAB plays a key role in the formation of alloy Au-Pd nanostructures. When CTAB is absent, the products are typical core-shell nanostructures. Moreover, the as-prepared nanostructures exhibit excellent electrocatalytic ORR performance in alkaline media, especially for Au-Pd alloy nanostructures. The overpotential of oxygen reduction gets reduced significantly, and the peak potential is positive-shifted by 44 and 34 mV in comparison with the core-shell ones and Pd/C catalyst, respectively. Thus, the controllable preparation and excellent electrocatalytic properties will make them become a potentially cheaper Pd-based cathodic electrocatalyst for DAFCs in alkaline media.

In this article, AgVO3@AgBr@Ag nanobelt heterostructures were fabricated as an efficient visible-light photocatalyst through a hydrothermal process, an anion-exchange reaction, and a light-induced reduction. SEM and TEM characterization revealed that anion exchange followed by light-induced reduction is an efficient method to synthesize well-dispersed AgBr@Ag nanoparticles on the surface of AgVO3 nanobelts. The composite photocatalyst efficiently combines visible-light active AgBr and AgVO3 with the surface plasmon resonance (SPR) effect of Ag nanoparticles. The obtained catalyst displayed a high performance for removing organic dye in the range of visible light. This improved visible-light response likely originates from a synergistic effect of the different components. This work provides a versatile approach for accessing efficient, stable, and recyclable visible-light-driven plasmonic photocatalysts.

No abstract

In this work, we utilize the galvanic displacement synthesis and make it a general and efficient method for the preparation of Au-M (M = Au, Pd, and Pt) core-shell nanostructures with porous shells, which consist of multilayer nanoparticles. The method is generally applicable to the preparation of Au-Au, Au-Pd, and Au-Pt core-shell nanostructures with typical porous shells. Moreover, the Au-Au isomeric core-shell nanostructure is reported for the first time. The lower oxidation states of Au(I), Pd(II), and Pt(II) are supposed to contribute to the formation of porous core-shell nanostructures instead of yolk-shell nanostructures. The electrocatalytic ethanol oxidation and oxygen reduction reaction (ORR) performance of porous Au-Pd core-shell nanostructures are assessed as a typical example for the investigation of the advantages of the obtained core-shell nanostructures. As expected, the Au-Pd core-shell nanostructure indeed exhibits a significantly reduced overpotential (the peak potential is shifted in the positive direction by 44 mV and 32 mV), a much improved CO tolerance (I(f)/I(b) is 3.6 and 1.63 times higher), and an enhanced catalytic stability in comparison with Pd nanoparticles and Pt/C catalysts. Thus, porous Au-M (M = Au, Pd, and Pt) core-shell nanostructures may provide many opportunities in the fields of organic catalysis, direct alcohol fuel cells, surface-enhanced Raman scattering, and so forth.

No abstract