Anisotropic gold nanostructure-mediated electrocatalysis on exfoliated GCN: A shape-dependent study

Abstract

The growth of anisotropic gold nanostructures on exfoliated GCN(E-GCN) surface and the resulting shape dependent electrocatalytic activity towards ascorbic acid (AA), dopamine (DA) and hydrogen peroxide (HP) were investigated in this present study. The SEM images of Au deposited on GC surface shows anisotropic structures after 120 min deposition. On the other hand, Au deposited on E-GCN after 15 min shows flower like structure (GCE/E-GCN-FL-Au) and it remains unchanged up to 60 min. The flower like morphology was changed to distorted hexagonal morphology after 120 min deposition (GCE/E-GCN-DH-Au) Here, citric acid (CA) can act as a reducing agent for the reduction of Au3+ to Au0. The obtained morphological changes of Au on the surface of E-GCN in contrast to GC plate, reveal that the GCN surface can act as a shape directing agent. The electroactive surface area (EAS) of the GCE/E-GCN-DH-Au was greater than the EAS of the GCE/E-GCN-FL-Au. The influence of Au shape on AA and DA oxidation and HP reduction was also investigated. In terms of electrochemical determination towards AA, DA and HP, the GCE/E-GCN-DH-Au outperformed the other modified electrodes. The GCE/E-GCN-DH-Au proved to be a useful tool for sensitive determination of HP with the LOD of 0.75 nM (S/N=3).