Ultrasensitive Dopamine Detection at Co₃O₄-Anchored N-Doped Hollow Mesoporous Carbon Nanospheres

The spinel type of metal oxide decoration with a heteroatom (N)-doped mesoporous carbon hollow sphere offers an excellent electrocatalyst and increases the probability of survival in detection of sensor applications. Here, we develop a single-step and effective hard template strategy for the excellent detection of dopamine (DM) with the utilization of the cobalt precursor cobalt phthalocyanine (CoPc). The optimum 0.2 g-loaded CoPc and the resulting cobalt oxide (Co 3 O 4 )-anchored nitrogen-doped hollow carbon sphere (Co 3 O 4 /NDHCS-0.2) material demonstrate the admirable sensing performance toward DM detection. The remarkable sensing performance is mainly ascribed to the stable mesoporous hollow carbon sphere and its better thickness, large surface area, defect sites, higher decoration of Co content, and higher concentrations of octahedral Co 3+ and pyridine N centers, and its Co 3+ /Co 2+ ratio. The obtained Co 3 O 4 /NDHCS-0.2/GCE material achieves wide linear ranges from 1.0 to 900 and 1500 to 6500 μM, low limits of detection of 11 nM and 0.516 μM, and high sensitivities (871 and 103 μA mM –1 cm –2 ). The proposed sensor was also employed to test the practical application of the real samples. The dopamine sensor has also shown long-term stability and acceptable reproducibility.