Bifunctional Ag@Ni-MOF for high performance supercapacitor and glucose sensor

Abstract

In this work, Ag nanoparticles (NPs) doped Ni-MOF was prepared by hydrothermal synthesis followed by chemical reduction. The size of Ag NPs is about 20 nm and dispersed between the nanosheets of Ni-MOF, which increases the surface area and pore size of Ni-MOF. As a result, the specific capacitance of the Ag@Ni-MOF electrode increases from 820 F/g (Ni-MOF) to 1312 F/g at a current density of 1 A/g due to the improved conductivity and enhanced diffusion of electrolyte. After 3000 cycles of charge-discharge, the remaining specific capacitance is 80% of the initial value in a two-electrode system, compared with the low cycle stability of Ni-MOF (60%). Moreover, the Ag@Ni-MOF coated GCE electrode displays excellent electrochemical performance as a non-enzymatic glucose sensor. In 0.1 M NaOH solution and under 0.5 V working voltage, the composite electrode exhibits a wide linear detection range of 5–500 μM and a sensitivity of 160.08 μA cm−2 mM−1. The detection limit reaches 5 μM (S/N = 3). Meanwhile, the Ag@Ni-MOF/GCE electrode reveals good performance in the anti-interference experiment and stability experiment as well.