Renewable Sandwich Roll-Like Electrode Based on Hollow Ni-NiCx Microsphere and MXene for Constructing a Portable Non-Enzymatic Glucose Sensor

A renewable electrode without relying on traditional supporting electrodes is expected to reduce the use-cost and improve the testing efficiency. Herein, a novel renewable electrode that is hollow Ni-NiCx microspheres@carbonized rice-paper@few-layer Ti3C2Tx nanosheets (Ni-NiCx@CRP@Ti3C2Tx) is prepared through the processes of drop-casting, curling, pyrolysis, and molding. Such a Ni-NiCx@CRP@Ti3C2Tx electrode with sandwich roll-like structure can be directly utilized as the working electrode for non-enzymatic glucose sensing. The main performance parameters include 0.5-280.0 μM of linear detection range, 79 nM of detection limit, and 2860 μA mM-1 cm-2 of sensitivity. The high-performance behaviors of Ni-NiCx@CRP@Ti3C2Tx electrode are attributed to the optimized interlayer relationships of the sandwich roll-like structure. First, the Ni-NiCx layer provides high-efficiency active sites for the electrochemical oxidation of glucose. Second, the Ti3C2Tx layer provides an excellent conductive network for the collection of electrochemical signals. More importantly, the rapidly renewable strategy of Ni-NiCx@CRP@Ti3C2Tx electrode is proposed through the self-designed electrode shear for 1st-10th cutting. Ultimately, a prototype of portable electrochemical sensor composed of the renewable Ni-NiCx@CRP@Ti3C2Tx electrode, the adjustable working electrode system and the self-designed electronic system is established for detecting glucose in urine sample. Our work presents a novel approach for developing renewable electrodes for electrochemical sensing.