Ag-doped zeolitic imidazolate framework-8 nanoparticles modified CPE for efficient electrocatalytic reduction of H₂O₂

Highlights: • ZIF-8 nanoparticles were synthesized using a simple room temperature method. • For the first time, Ag-doped ZIF-8 nanoparticles were used to detect H₂O₂. • Ag/ZIF-8/CPE shows excellent catalytic performance toward H₂O₂ reduction. • This sensor indicates wide linear range, low detection limit, high sensitivity and good selectivity. - Abstract: Zeolitic imidazolate framework-8 (ZIF-8) is one of the three dimensional porous metal-organic frameworks consisting of highly accessible pores and great surface area. In this study, ZIF-8 nanoparticles were synthesized and then characterized using X-ray diffraction (XRD), Fourier transform infrared (FT-IR), scanning electronic microscopy (SEM) and Brunauer–Emmett–Teller (BET) methods. A carbon paste electrode was modified with ZIF-8 nanoparticles doped with Ag (Ag/ZIF-8/CPE) and then used as an electrochemical sensor to detect hydrogen peroxide (H₂O₂). The response of modified electrode toward H₂O₂ reduction was examined using cyclic voltammetry and amperometry. Cyclic voltammetry studies revealed that the modified electrode can increase the reduction current of H₂O₂. Amperometric response of this sensor shows linear relationship over the concentration ranges of 20 μM to 5 mM and 5.5 mM to 10 mM, with low detection limit of 6.2 μM (S/N = 3), high sensitivities of 398.47 and 145.21 μA mM⁻¹ cm⁻² and a good response time of 4 s. The Ag/ZIF-8/CPE also indicates good anti-interference performance toward ascorbic acid, uric acid, glucose and sucrose during detection of H₂O₂. Modification of ZIF-8/CPE with Ag can be a useful method for developing new sensitive and selective H₂O₂ electrochemical sensors