Ordered SiO2 cavity promoted formation of gold single crystal nanoparticles towards an efficient electrocatalytic application

Abstract

A highly ordered SiO₂ cavity array was fabricated on the surface of ITO glass using a monolayer of polystyrene as the template. Gold nanoparticles (AuNPs) were implanted into the bottom of each cavity via an electrochemical deposition method due to the confinement effects of the SiO₂ cavity. These AuNPs were further transformed into a [111] facet dominated single particle during a mild calcination process. The as-prepared Au single-crystal/SiO₂ cavity modified electrodes (AuSC/SCME) were characterized by SEM, XRD, and HRTEM, and the improved electro-catalytic ability of such electrodes for the oxidation of ethanol was verified by several electrochemical experiments. In addition, the catalytic mechanism was also discussed based on the fixed crystal facets of the AuSCs and the confinement effect of the SiO₂ cavities. Furthermore, the catalytic application of the AuSCs was extended to the oxidation of nitrite.