This work develops an in situ electrodeposition strategy to construct a honeycomb-like Ni/Co-MOF/MXene heterojunction directly on the glassy carbon electrode (GCE) surface at −1.3 V vs. Ag/AgCl, enabling ultrasensitive enzymatic electrochemical detection of trace urea. The high catalytic activity of Ni/Co-MOF and the superior conductivity of MXene were synergistically integrated in a 3D hierarchical heterostructure. Compared with traditional modification methods, this strategy significantly enhances the kinetics of electron transfer and the stability of urease immobilization. Characterized by scanning electron microscopy (SEM) and electrochemical impedance spectroscopy (EIS), the heterojunction exhibits unique morphology and outstanding electroconductivity. Furthermore, the resulting Ni/Co-MOF/MXene/urease/GCE biosensor achieves a wide linear range of 1.0 × 10 –6 –1.0 × 10 –4 mol L −1 with a low detection limit of 4.9 × 10 –7 mol L −1 . The biosensor has been applied to the detection of practical samples, where the recoveries were 99.3–102.8% with a relative standard deviation (RSD) of 2.9–3.3%, which indicates that this biosensor has good practical applications and prospects for further development.
Gao et al. (Sat,) studied this question.