Electroless deposition of Gold-Platinum Core@Shell Nanoparticles on Glassy Carbon Electrode for Non-Enzymatic Hydrogen Peroxide sensing

A non-enzymatic hydrogen peroxide sensor was developed using gold@platinum nanoparticles (Au@PtNPs) with core@shell structure fabricated on glassy carbon electrode (GCE) by electroless deposition method. Initially, gold nanoparticles (AuNPs) were deposited on GCE by reducing HAuCl4 in the presence of NH2OH and the deposited AuNPs on GCE act as the nucleation centre for the deposition of platinum nanoparticles (PtNPs) in the presence of H2PtCl6 and NH2OH. SEM and AFM studies demonstrated that the electroless deposition of Pt on Au was isotropic and uniform. Further, Au@PtNP-modified substrates were characterized by X-ray photoelectron spectroscopy (XPS), energy dispersive X-ray analysis (EDAX) and cyclic voltammetry (CV). XPS showed characteristic binding energies at 71.2 and 74.4 eV for PtNPs and, 83.6 and 87.3 eV for AuNPs indicating the zero-valent nature in both of them. The electrocatalytic activity of Au@PtNP-modified electrode was investigated towards hydrogen peroxide (HP) reduction. The modified electrode exhibited higher electrocatalytic activity towards HP by not only shifting its reduction potential by 370 mV towards less positive potential but also by enhancing the reduction current when compared to bare and AuNP-modified GCE. The present method shows better sensitivity compared to the reported methods in literature and the detection limit was found to be 60 nM.