3D hierarchical hollow hydrangea-like Fe3+@ɛ-MnO2 microspheres with excellent electrochemical performance for dopamine and hydrogen peroxide.

Construction a sensor to accurately detect dopamine (DA) and hydrogen peroxide (H₂O₂) is meaningful due to their close relation to the health of organisms. In this work, one-step hydrothermal method was employed to synthesize hierarchical hollow hydrangea-like Fe³⁺@ɛ-MnO₂ microspheres constructed by interconnected nanosheets, and the growth mechanism of the microspheres (n_Fe/n_Mn = 0.6) was also investigated in detail. The material was used to construct an electrochemical sensor for DA and H₂O₂ detection with the linear range of 0.02-78 μmoL^-1 and 0.000133-5.19 mmoL^-1, respectively. The detection limit and sensitivity for DA and H₂O₂ are 5 and 50 nmoL^-1 (S/N = 3), 7034.1 and 242.6 µA m(mol·L^-1)^-1 cm^-2, respectively. Furthermore, the sensor was successfully applied to the detection of DA and H₂O₂ in serum and urine samples, indicating a potential value of this work in the pharmaceutical and environmental fields.