Gold nanobipyramids doped with Au/Pd alloyed nanoclusters for high efficiency ethanol electrooxidation

Plasmonic metal nanostructures are of great interest due to their excellent physicochemical properties and promising applications in a wide range of technical fields. Among metal nanostructures, bimetallic nanostructures with desired morphologies, such as core-shell, uniform alloy and surface decoration, are of great interest due to their improved properties and superior synergetic effects. In this paper, Au/Pd nanoclusters were deposited on the surface of gold nanobipyramids (AuBPs) into a core-shell nanostructure (AuBP@Au x Pd1-x ) through a reductive co-precipitation method. The AuBP@Au x Pd1-x nanostructure integrates effectively the advantages of plasmonic AuBPs and catalytic Pd ultrafine nanoclusters, as well as the stable Au/Pd alloy shell. The AuBP@Au x Pd1-x nanostructure exhibits superior electrocatalytic activity and durability for oxygen reduction in alkaline media owing to the synergistic effect between the AuBP core and Au/Pd shell. Furthermore, the shell thickness of AuBP@Au x Pd1-x nanostructures can be adjusted by varying the amount of precursor. Overall, the catalytic activity of bimetallic Au/Pd catalysts is likely to be governed by a complex interplay of contributions from the particle size and shape.

An environmentally friendly one-pot synthesis method by the ultrasound assistance for the decoration of ultrasmall Pd-Ag NPs on graphene as high active anode catalyst towards ethanol oxidation

An environmentally friendly one-pot synthesis approach for the decoration of Pd-Ag nanoparticles with the ultrasmall size on graphene (Pd-Ag/G) by the assistance of ultrasound is proposed in this paper. This method offers exceptional advantages over other approaches such as environmentally friendly synthesis, being low temperature, reductant, surfactant free, simple, fast and one-pot synthesis. In this work, silver formate is added to the graphene suspension at 25 °C. Then, PdCl₂ is added to the suspension under stirring to fabricate Pd-Ag/G. The uniform dispersity of nanoparticles with an average size of about 2-3 nm is well confirmed by transmission electron microscopy micrographs. The resultant catalyst is applied as anode electrocatalyst towards electrooxidation reaction of ethanol. The Pd-Ag/G catalyst displays exceptional catalytic activity and durability towards electro-oxidation of ethanol. According to the obtained results, it be concluded that the combination of Ag and Pd, ultrasmall and uniform distribution of Pd-Ag nanoparticles led to the improvement of electrocatalytic activity of the Pd-Ag/G catalyst.

Hollow Echinus-like PdCuCo Alloy for Superior Efficient Catalysis of Ethanol

Large-scale preparation of hollow echinus-like PdCuCo alloy nanostructures (HENSs) with a high surface area-to-volume ratio, rich active sites, and relatively efficient catalytic activity has attracted considerable research interest. Herein, we present an economic and facile approach to synthesize HENSs by galvanic exchange reactions using Co nanospheres as sacrificial templates. Moreover, the catalytic activity could be adjusted via changing the composition of the catalyst. The composition, morphology, and crystal structure of the as-obtained nanomaterials are characterized by various techniques, such as inductively coupled plasma atomic emission spectrometry, transmission electron microscopy, and X-ray diffraction. Electrochemical catalytic measurement results prove that the Pd₇₅Cu₈Co₃ catalyst obtained under optimal preparation conditions exhibits 10-fold higher activity for ethanol oxidation in comparison with the commercially available 20% Pd/C catalyst. The eminent performance of the Pd₇₅Cu₈Co₃ electrochemical catalyst could be ascribed to the peculiar echinus-like nanostructures.

Arginine-assisted synthesis of palladium nanochain networks and their enhanced electrocatalytic activity for borohydride oxidation

Three-dimensional Pd nanochain networks (Pd-NCNs) were prepared by an arginine-assisted self-assembly process, exhibiting excellent electrocatalytic performance towards the borohydride oxidation reaction.

Synthesis of chestnut-bur-like palladium nanostructures and their enhanced electrocatalytic activities for ethanol oxidation

We report a facile method for the synthesis of Pd nanostructures with highly open structure and huge surface area by reducing Na₂PdCl₄ with ascorbic acid and using cetylpyridinium chloride (CPC) as a surfactant in an aqueous solution. The prepared Pd nanostructures had an average overall size of 70 nm and were composed of dozens of needle-like thin arms, originating from the same core, with an average thickness of 2.3 nm; the arms looked like chestnut-burs. Time evolution of Pd nanostructures implied that small Pd particles generated at the early stage of the reaction by fast reduction grew via the particle attachment growth mechanism. The morphology and size of the Pd nanostructures could be readily controlled by varying the concentration of CPC; depending on the amount of CPC, the reduction rates varied the morphology of the Pd nanostructures. Because of the huge surface area and possible catalytically active sites, the prepared chestnut-bur-like Pd nanostructures exhibited greater electrocatalytic activity toward ethanol electrooxidation compared to other Pd nanocatalysts, including cubic and octahedral Pd nanocrystals, and even commercial Pd/C.