A hollow urchin-like α-MnO₂ as an electrochemical sensor for hydrogen peroxide and dopamine with high selectivity and sensitivity

A hollow urchin-like α-MnO₂ material has been synthesized by a hydrothermal method starting from MnSO₄·H₂O and (NH₄)₂S₂O₈, and by using silver(I) as the catalyst. It has a hollow morphology with diameters of 5–6 μm and consists of densely aligned nanowires, with a 30–40 nm width and a 1.5 μm length. The diameter of the cavities and the thickness of the shell are about 1.2 μm and 300 nm, respectively. The material was placed on a glassy carbon electrode (GCE), and electrochemical experiments showed the respective sensor to possess good stability and reproducibility. The modified GCE displays response to both hydrogen peroxide (H₂O₂) and dopamine (DA) at working potentials of −0.40 V and +0.4 V, respectively (both versus SCE). H₂O₂ can be detected with an 80 nM detection limit, and DA with a 12 nM detection limit (at S/N = 3).

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