Single Ag Nanowire Electrodes and Single Pt@Ag Nanowire Electrodes: Fabrication, Electrocatalysis, and Surface-Enhanced Raman Scattering Applications

Abstract

Silver nanowires (AgNWs) have received much attention due to their excellent optical, electrical, and conductive properties. In this work, we provided a new perspective for investigating the property of AgNWs from a single nanowire level. Single Ag nanowire electrodes and single Pt@Ag nanowire electrodes were fabricated by a laser-assisted pulling technique and galvanic replacement reaction (GRR). The radius, length, and metal ratio of the nanowires are tunable as needed. The prepared nanowire exhibited excellent electrocatalytic activity toward the methanol electro-oxidation and high sensitivity for monitoring the reduction of 4-nitrothiophenol by recording SERS spectra. This work will help us deeply understand the catalytic performance at the single nanowire level and open a new perspective for nanomaterials research.

Palladium‐Coated Single Silver Nanowire Electrodes: Size‐Dependent Voltammetry, Enhanced Chemical Stability, and High Performance for Methanol Oxidation

“…Bimetallic nanomaterials expose fascinating properties through introducing a second metal that not only improves electrochemical performance but also reduces cost, which are of great interest for fuel cells, electrocatalysis, sensing, and bioanalysis . Due to the standard reduction potential of Ag + / Ag (+0.7991 V) is lower than the reduction potential of Pd 2+ / Pd (+0.951 V), it could be determined that galvanic displacement reaction facilitates the formation Pd–Ag bimetallic nanostructure by using AgNWs as sacrificial templates . Here, we have successfully prepared palladium‐coated silver nanowire electrodes (Pd@AgNWEs) based on the following equation [Eq.…”

“…The EDS data (Figure B) also proved that Pd was immobilized on AgNWE surface through the atomic ratio of Pd/Ag (≈0.6). From the HRTEM images of Pd@AgNWEs (Figure C and D), it was clearly observed that crystal lattice fringe spacing of Pd@AgNWEs was 0.229 nm, which was located between the values of the (111) planes of face‐centered cubic (fcc) Pd (0.225 nm) and Ag (0.236 nm); this indicated that Ag‐Pd alloy was formed and the (111) plane was the main facet . All of these results indicate that Pd@AgNW was fabricated successfully.…”

“…Moreover, the onset potential (−0.48 V) from Pd@AgNW was much more negative than that from commercial Pd/C (−0.3 V), indicating the higher catalytic activity towards MOR from Pd@AgNW (Figure S3). The anodic peak current density in the forward scan can be used to evaluate the catalytic activities of the catalysts . The current density of Pd@AgNW was 29.32 mA cm −2 , which was much higher than the value obtained from commercial Pd/C (3.17 mA cm −2 ), indicating that the Pd@AgNWs had much higher catalytic activity.…”

“…From the slight decrease (≈7.3 %) of the current density, it could be obtained that Pd@AgNWs had excellent stability for methanol electro‐oxidation. It is well known that the ratio of forward peak current to the backward peak current ( I f / I b ) can be applied as a significant index to reflects the tolerance of the catalyst . However, I f / I b is not related to the degree of CO tolerance but to the degree of oxophilicity indeed which was reported by Sung et al .…”

The Hybrids of Core‐Shell Chain‐like Nanostructure of Au@Porous Pd with Graphene for Energy Conversion Application

“…[11] Similarly, Wang et al developed the Pt@Ag nanowires and checked their methanol oxidation activity. [12] Tang et al also developed the PtÀ Pd bimetallic NPs by electrodeposition method and observed a higher methanol oxidation activity. [13] Efforts of many groups across the world make it possible to construct a myriad of polyhedral shaped Au@Pd core-shell nanostructures, which include cubes, rods, octahedral and rhombic dodecahedra.…”