Nickel Based Metal Organic Framework/Reduced Graphene Oxide Composite as Electrode Material for the Voltammetric Detection of Caffeine

Abstract

Herein, a sensing platform was constructed by the integration of nickel based metal organic framework (MOF) and reduced graphene oxide (RGO) by sonication assisted preparation. The morphology and structural features of the composite were confirmed using scanning electron microscopy, infrared spectroscopy and X-ray photoelectron spectroscopy respectively. The synergistic effect which arise from the combination of porous nature of MOF and higher electrical conductivity of RGO makes the composite a promising electrode material for electrochemical sensing. The prepared composite was employed for the highly sensitive electrochemical detection of caffeine. The electrochemical characteristics of the modified electrodes and the electrochemical performance of the sensor were evaluated. The electrocatalytic oxidation of caffeine on Ni-MOF/RGO was confirmed as diffusion controlled, irreversible and two electron transfer process. The proposed sensor exhibited a wide linear concentration range of 0.1–250 μM with two linear segments and limit of detection 0.04 μM and 5.29 μM respectively. Further, the electrochemical sensor shows higher selectivity, satisfactory stability and repeatability for caffeine sensing. This work highlights the formation of a composite via direct assembly of Ni-MOF and RGO by a simple sonication method and its application as sensing material for caffeine by utilizing the high sorption potential of MOF.