Ni-Al/layered double hydroxide/Ag nanoparticle composite modified carbon-paste electrode as a renewable electrode and novel electrochemical sensor for hydrogen peroxide

In the present study, a simple and highly sensitive electrochemical method was developed for the determination of hydrogen peroxide (H 2 O 2 ) through a Ni-Al/layered double hydroxide/Ag nanoparticle composite modified carbon-paste electrode (Ni-Al/LDH/Ag NPs/CPE) as a renewable electrode in 0.1 M phosphate buffer solution (PBS, pH = 7.0). Scanning electron microscopy (SEM), atomic force microscopy (AFM), and X-ray diffraction (XRD) were performed for the characterization of the Ni-Al/LDH/Ag NP composite. The electrocatalytic activity of the Ni-Al/LDH/Ag NPs/CPE for H 2 O 2 reduction was studied by cyclic voltammetry and chronoamperometric (at an applied potential of −0.9 V) methods. The prepared renewable modified electrode as a H 2 O 2 sensor shows good electrocatalytic activity, fast response time, good stability and reproducibility. The present sensor also displays a linear range from 10 μM to 10 mM concentration of H 2 O 2 with a detection limit of 6 μM (S/N = 3) and sensitivity of 1.863 μA mM −1 cm −2 . This sensor was employed successfully for the determination of H 2 O 2 in real samples by the chronoamperometric method, which indicates its applicability in practical analysis. Cyclic voltammograms of the bare CPE (a and c) and Ni-Al/LDH/Ag NPs/CPE (b and d) respectively in the presence and absence of. Inset is cyclic voltammograms Ni-Al/LDH/CPE in the absence (a) and presence (b) of H 2 O 2 .