A Sensitive Electrochemical Sensor Based on Hollow Spindle Ferric Oxide for the Determination of Hydrogen Sulfide

A one-step hydrothermal synthesis method was used to synthesize ferric oxide nanoparticles with unique hollow spindle microstructure, which were mixed with conductive carbon black (CCB) to construct an electrochemical sensor to realize the highly sensitive detection of trace hydrogen sulfide (H₂S) in biological samples. Our findings suggested that hollow spindle ferric oxide (Hs-Fe₂O₃) held good electrocatalytic activity toward H₂S, which mainly depended on the coupling effect of Fe (III)/Fe (II) significantly reduced the overpotential of electro-oxidation reaction of H₂S. Importantly, the unique structure of the hollow spindle provided more catalytic active sites and more efficient mass transfer process, which effectively improved the detection performance. The proposed sensor had good sensing performances, with excellent sensitivity (2.4 times of commercial Fe₂O₃/CCB), low detection limit (1.86 μM), wide linear range (7.6~152 μM) and favorable selectivity. Furthermore, quantitative detection of H₂S was achieved in fetal bovine serum samples, which confirmed that the sensor could become a promising strategy for detecting H₂S in the pathological study of related diseases.