Hybrid of dandelion-like hollow Mo₂C nanospheres-graphene nanosheets as the electrode for highly sensitive electrochemical detection of dopamine

Molybdenum polydopamine hollow nanospheres were synthesized by liquid-phase reactions at room temperature and they were transformed into molybdenum carbide (Mo2C) when annealed at 800 degrees C. Subsequently, they were self-assembled with graphene oxide (GO) and sprayed onto the indium tin oxide (ITO) glass. After heating at 400 degrees C, the Mo2C-reduced GO/ITO (Mo2C-rGO/ITO) electrode was obtained and used for the detection of dopamine (DA). The results show that Mo2C is made up of dandelion-like hollow nanospheres with an outer and inner diameter of 500 and 200 nm, and Mo2C is homogeneously mixed with rGO nanosheets. Due to the synergistic effect of the excellet electrocatalytic properties of Mo2C and electrical conductivity of rGO, the hybrid Mo2C-rGO/ITO electrode shows a high sensitivity (8.30 mu A.mu M-1.cm(-2)) and a low limit of detection (LOD) (0.058 mu M, S/N = 3) for DA in the range of 0-60 mu M. Additionally, the electrode shows a good repeatability and stability, and it is also successfully used for the determination of DA in diluted human urine. It has a great potential for clinical applications.