Nanoparticles of Cu₂O and TiO₂ on Ti₃C₂T_x Heterostructures for Ultrafast Nonenzymatic Glucose Sensing

The exploration of enzyme-mimic nanocomposites to replace commercial enzymes is challenging in the construction of biosensors with high performance. Herein, an ultrafast response nonenzymatic glucose sensor was developed based on a Cu 2 O–TiO 2 /Ti 3 C 2 T x nanocomposite, which was prepared via an in situ redox procedure using Ti 3 C 2 T x nanosheets both as a reducing agent and a carrier substrate. Structural characterizations, including X-ray diffraction (XRD) and transmission electron microscopy (TEM), revealed that Cu 2 O nanoparticles with a size of 10–30 nm are uniformly distributed on the surface of the Ti 3 C 2 T x nanosheets and form close contacts through Ti–O–Cu bonds, resulting in favorable stability of the system. The unique heterostructure of Cu 2 O–TiO 2 /Ti 3 C 2 T x can produce abundant active sites and facilitate electron transfer, demonstrating enhanced catalytic activity in the electrooxidation of glucose. Consequently, the electrochemical sensor fabricated by modifying a glassy carbon electrode (GCE) with Cu 2 O–TiO 2 /Ti 3 C 2 T x nanocomposites exhibited excellent analytical properties for glucose detection, including a fast response time of 0.1 s, a low detection limit of 0.67 μM, and a high sensitivity of 267 μA mM –1 cm –2 . In addition, the developed method possesses good anti-interference ability and superior stability and thus has been successfully applied for real sample monitoring. This study offers a way to construct Ti 3 C 2 T x -based heterostructures with tunable physiochemical properties and expands their use in the electrochemical field.