Nickel nanoparticles incorporated Co, N co-doped carbon polyhedron derived from core-shell ZIF-8@ZIF-67 for electrochemical sensing of nitrite

Abstract

Herein, a novel electrochemical sensor based on core-shell zeolitic imidazolate framework-8 @zeolitic imidazolate framework-8 ([email protected]) derived cobalt and nitrogen co-doped carbon polyhedron (Co, N-CP) and electrodeposited nickel nanoparticles (Ni NPs) was developed for nitrite (NO2−) detection. The Co, N-CP was prepared by direct pyrolysis of the core-shell structured [email protected] at Zn/Co at 900 °C in an Ar atmosphere. Ni NPs were electrodeposited on Co, N-CP modified glass carbon electrode (Co, N-CP/GCE) using potentiostatic method. The Ni NPs decorated Co, N-CP displays a synergetic electrocatalytic effect for the oxidation of NO2− due to the large surface area and ordered porosity of Co, N-CP integrating the good conductivity and catalytic activity of Ni NPs. The proposed sensor exhibited good electrocatalytic activity, sensitivity and selectivity towards NO2− with the catalytic rate constant (Kcat) of 5.49 × 106 M−1 s−1 and the diffusion coefficient (D) of 5.12 × 10−6 cm2 s−1. The Ni/Co, N-CP/GCE showed a wide linear response (5–1000 μM) and a low detection limit (LOD) of 0.094 μM (S/N = 3). Additionally, the sensor was successfully applied to monitor NO2− in real samples with satisfactory recoveries, indicating that Ni/Co, N-CP could be a promising candidate for sensing of other biologically important molecules.