Electronic and Magnetic Properties of Ultrathin Au/Pt Nanowires

Abstract

We have reported the synthesis of Au(25)Pt(75) and Au(48)Pt(52) alloyed ultrathin nanowires with average widths of less than 3 nm via a wet chemistry approach at room temperature. Using a combination of techniques, including scanning transmission electron microscopy equipped with X-ray energy dispersive spectroscopy, ultraviolet-visible spectroscopy, and X-ray absorption near-edge structure and extended X-ray absorption fine structure spectroscopies, we identified the stoichiometry-dependent heterogeneous crystalline structures, as well as electronic structures with respect to the charge transfer between Pt and Au within both nanowires. In particular, we observed d-charge depletion at the Au site and the d-charge gain at the Pt site in Au(48)Pt(52) nanowires, which accounted for its ferromagnetic magnetic behavior, in contrast to the paramagnetism and diamagnetism appearing respectively in bulk Pt and Au.

Noble metal alloy complex nanostructures: controllable synthesis and their electrochemical property

“…86 In this review, we tend to refer to the ultrathin nanocrystals with further decreased dimension to sub-5 nm or even 1 nm. [90][91][92] To obtain such structures, their favorable isotropic growth mode should be broken and the growth direction should be confined along one certain direction with the other two directions inhibited. 86,89 Especially as electrochemical catalysts, the ultrathin structures can potentially provide a high specific surface area and consequent promising catalytic performance.…”

Understanding of the major reactions in solution synthesis of functional nanomaterials

“…Heterojunction nanostructures constructed with different building blocks of nanoscale dimensions have attracted special attention owing to their unique and tailored properties for various applications in materials science [357][358][359][360][361][362][363][364]. The galvanic replacement is a straight-forward method to prepare heterojunction nanomaterials through partial replacement of one metal NP with another metal component [365,366].…”

Superior electrocatalytic activity of ultrathin PtPdBi nanowires towards ethanol electrooxidation

“…Alloying with other metal(s) may endow Pt catalyst with an enhanced tolerance to poisoning intermediates 1,2 by either synergistic catalytic effect 3,4 or electronic structural effect, 5 such as PtAu, 5 PtPd, 6,7 PtRh, 8 PtBi, 9 PtFe, 10 PtPdAu, 11 PtRhNi, 12 PtSn, 13 and PtMn 14 alloy catalysts, where PtPd alloy catalyst is particularly the center of attention because alloying with Pd not only modulates d-band electronic structure of Pt, 2,15 weakening the adsorption of poisoning molecules, but also introduces co-catalytic effect, 7,16 especially in catalytically oxidizing methanol or ethanol in basic solution, in which Pd even exhibits much better electrocatalytic activity and stability than Pt. Alloying with other metal(s) may endow Pt catalyst with an enhanced tolerance to poisoning intermediates 1,2 by either synergistic catalytic effect 3,4 or electronic structural effect, 5 such as PtAu, 5 PtPd, 6,7 PtRh, 8 PtBi, 9 PtFe, 10 PtPdAu, 11 PtRhNi, 12 PtSn, 13 and PtMn 14 alloy catalysts, where PtPd alloy catalyst is particularly the center of attention because alloying with Pd not only modulates d-band electronic structure of Pt, 2,15 weakening the adsorption of poisoning molecules, but also introduces co-catalytic effect, 7,16 especially in catalytically oxidizing methanol or ethanol in basic solution, in which Pd even exhibits much better electrocatalytic activity and stability than Pt.…”