<em>In-situ</em> Electrodeposition of FeCo-MOF on Au Ultramicroelectrode for Highly Sensitive Detection of Epinephrine

Metal-organic framework (MOF) nanostructures have emerged as a prominent class of materials in the advancement of electrochemical sensors. The rational design of bimetallic MOF-functionalized microelectrode is of importance for improving the electrochemical performance but still in great challenge. In this work, the bimetallic FeCo-MOF nanostructures were assembled onto a gold disk ultramicroelectrode (Au UME, 5.2 μm in diameter) via an in-situ electrodeposition method, which enhanced the sensitive detection of epinephrine (EP). The in-situ electrodeposited FeCo-MOF exhibited a characteristic nanoflower-like morphology and was uniformly dispersed on the Au UME. The FeCo-MOF/Au UME demonstrated excellent electrochemical performance on the detection of EP with a high sensitivity of 36.93 μA·μmol–1·L·cm–2 and a low detection limit of 1.28 μmol·L–1. It can be attributed to the nonlinear diffusion of EP onto the ultra-micro working substrate, coupled with synergistical catalytic activity of the bimetallic Fe, Co within MOF structure. Furthermore, the FeCo-MOF/ Au UME has been successful applied to the analysis of EP in human serum samples, yielding high recovery rates. These results not only contribute to the expansion of the research area of electrochemical sensors, but also provide novel insights and directions into the development of high-performance MOF-based electrochemical sensors.