Development of non-enzymatic and highly selective hydrogen peroxide sensor based on nanoporous gold prepared by a simple unusual electrochemical approach

A high surface area nanoporous gold film electrode (NPGF) was prepared by a simple electrochemical route instead of the well-known alloying/dealloying method. Field emission scanning electron microscopy (FE-SEM) and energy dispersive X-ray analysis (EDX) were used to investigate the surface morphology and elemental composition of the as-prepared NPGF electrode. The electrocatalytic activity and sensing behaviour of the developed non-enzymatic NPGF electrode was demonstrated towards hydrogen peroxide (H2O2) reduction employing cyclic voltammetry and amperometry techniques. Cyclic voltammetric measurements confirmed the excellent catalytic activity of the NPGF electrode as a shift in the overpotential (~ 0.4 V) towards less negative direction along with increased current signal compared to the unmodified bare Au electrode were noticed. Additionally, the H2O2 reduction on the NPGF electrode takes place at less negative potential values in comparison with those found for existing NPG electrodes prepared by alloying/dealloying method. The electrochemical sensing of H2O2 at the NPGF electrode was evaluated through amperometric mode by applying a constant potential of − 0.2 V in the linear range 10 × 10− 6 mol L− 1-1 × 10− 3 mol L− 1. The lower detection limit (LOD) was found to be 3.7 × 10− 6 mol L− 1 (S/N = 3) and a remarkable selectivity was observed in the presence of major interfering molecules like glucose, ascorbic acid, dopamine and uric acid with high sensitivity (400 μA mM− 1 cm− 2). Other analytical parameters such as reproducibility and stability were well-studied and satisfactory results were obtained. The developed NPGF was used as a sensor probe for H2O2 detection in real samples.