Surface-Nitrided Ni@Ni3N/NCNTs Heterostructures for Sensitive and Portable Nonenzymatic Glucose Detection

A heterostructured Ni@Ni 3 N/NCNTs electrocatalyst was rationally designed via a MOF-derived strategy combined with controlled surface nitridation to achieve highly efficient nonenzymatic glucose sensing. In this architecture, metallic Ni nanoparticles anchored on a three-dimensional N-doped carbon nanotube framework were selectively converted into a thin Ni 3 N surface layer, forming abundant Ni/Ni 3 N heterointerfaces while preserving a conductive Ni core. Electrochemical studies reveal that the engineered heterointerfaces significantly reduce charge-transfer resistance and increase electrochemically active surface area, thereby promoting the generation of NiOOH species and facilitating glucose oxidation. As a result, the Ni@Ni 3 N/NCNTs electrode exhibits a high sensitivity of 685.07 μA mM −1 cm −2 , a low detection limit of 0.34 μM, and a wide linear range of 1–7000 μM for nonenzymatic glucose detection. Furthermore, integration with a smartphone-enabled electrochemical platform enables portable and real-time glucose analysis, demonstrating the strong potential of this surface-engineered heterostructure for practical portable sensing applications.