A high-sensitive dopamine electrochemical sensor based on multilayer Ti3C2 MXene, graphitized multi-walled carbon nanotubes and ZnO nanospheres

[Display omitted] •Ti3C2/G-MWCNTs/ZnO nanocomposites have been applied to sensor for the first time.•G-MWCNTs and ZnO have enhanced the chemical stability and electrocatalytic properties of Ti3C2.•This sensor has low LOD of 3.3 nM and high sensitivity of 16 A/M.•The sensor showed satisfactory stability and accuracy in human serum samples.•The redox process and the electron transfer mechanism of DA have been investigated by DFT. Dopamine is one of the most important neurotransmitters in the human body, and its sensitive detection and quantification are important for the diagnosis, prevention, and treatment of related neurological diseases. Herein, a highly-sensitive dopamine electrochemical sensor has been constructed based on the two-dimensional transition metal carbide Ti3C2 MXene, graphitized multi-walled carbon nanotubes and ZnO nanospheres. Dopamine presents a standard reversible redox reaction on the sensor, and density flooding theory has been successfully applied to reveal the redox process of dopamine. Under optimal experimental conditions, the sensor exhibits a wide linear range (0.01–30 μM), low limit of detection (3.2 nM) and high sensitivity (16 A/M). Furthermore, the sensor has excellent stability and anti-interference ability, satisfactory accuracy in human serum samples, which can be used for the detection of actual samples. This work has provided a novel method for detecting dopamine and a new idea for the application of MXene and metal oxide semiconductor in electrochemical sensors.