In Situ Growing CuO/ZIF-8 into Nickel Foam to Fabricate a Binder-Free Self-Supported Glucose Biosensor

A binder-free self-supported CuO/ZIF-8@NiF electrode is fabricated with CuO/ZIF-8 particles in situ growth in nickel foam pores. ZIF-8 is first assembled inside the nickel foam pores and then Cu2+ is adsorbed around the surface of ZIF-8 crystal, and finally reduced and oxidized to form CuO. Scanning electron microscopy indicates CuO is uniformly distributed on the surface of ZIF-8. The Cu element is significantly increased from 1.16 to 30.91 mg·g–1 under the existence of ZIF-8 from inductively coupled plasma results. The electrochemical analyses show that the electrochemical active surface area of the CuO/ZIF-8@NiF electrode can be increased two times while its electronic transport resistance can be reduced to one-seventh compared with the CuO/ZIF-8/NiF electrode with CuO/ZIF-8 binding on the substrate. The detection tests exhibit enhanced electrochemical properties with a sensitivity of 5640 μA·mM–1·cm–2, a low detection limitation of 0.1 μM, and a linear detection range from 0.5 to 120 μM. The biosensor presents good anti-interference property, stability, and a 101.08–104.53% recovery rate.