Low-Temperature Vapor-Phase Synthesis of Single-Crystalline Gold Nanostructures: Toward Exceptional Electrocatalytic Activity for Methanol Oxidation Reaction

Abstract

Au nanostructures (Au NSs) have been considered promising materials for applications in fuel cell catalysis, electrochemistry, and plasmonics. For the fabrication of high-performance Au NS-based electronic or electrochemical devices, Au NSs should have clean surfaces and be directly supported on a substrate without any mediating molecules. Herein, we report the vapor-phase synthesis of Au NSs on a fluorine-doped tin oxide (FTO) substrate at 120 °C and their application to the electrocatalytic methanol oxidation reaction (MOR). By employing AuCl as a precursor, the synthesis temperature for Au NSs was reduced to under 200 °C, enabling the direct synthesis of Au NSs on an FTO substrate in the vapor phase. Considering that previously reported vapor-phase synthesis of Au NSs requires a high temperature over 1000 °C, this proposed synthetic method is remarkably simple and practical. Moreover, we could selectively synthesize Au nanoparticles (NPs) and nanoplates by adjusting the location of the substrate, and the size of the Au NPs was controllable by changing the reaction temperature. The synthesized Au NSs are a single-crystalline material with clean surfaces that achieved a high methanol oxidation current density of 14.65 mA/cm2 when intimately supported by an FTO substrate. We anticipate that this novel synthetic method can widen the applicability of vapor-phase synthesized Au NSs for electronic and electrochemical devices.

Thermal Atomic Layer Etching of Gold Using Sulfuryl Chloride for Chlorination and Triethylphosphine for Ligand Addition

“…AuCl 3 may quickly decompose to AuCl + Cl 2 . AuCl surface species may undergo a disproportionation according to , 3 AuCl → AuCl 3 + 2 Au The AuCl 3 may then desorb as Au 2 Cl 6 at 150 °C …”

Ultrasensitive Detection of Ovarian Cancer Biomarker Using Au Nanoplate SERS Immunoassay

“…Vapor-phase grown Au nanostructures have also been developed, providing single-crystallinity, ultraclean, and ultraflat surfaces [44,47]. Recently, atomically flat and ultraclean Au NPls have been employed for ultrasensitive biomolecular sensing and as stable plasmonic nanoantennae as well as efficient catalysts [48][49][50]. Atomically flat nanomaterial surfaces have been employed to establish effective interfaces with various systems, thus innovatively improving nanomaterial-based devices [44].…”