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

Graphical A low potential electrochemical sensor for H 2 S detection in neutral solution was developed based on hollow spindle ferric oxide (Hs-Fe 2 O 3 ). The excellent electrocatalytic activity of Hs-Fe 2 O 3 is attributed to the coupling effect of Fe (III)/Fe (II) redox mediators to effectively reduce the overpotential of H 2 S electrochemical oxidation. In addition, the hollow structure of the Hs-Fe 2 O 3 material provides a large specific surface area and a loose porous structure, which significantly improves the detection performance. 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 (H 2 S) in biological samples. Our findings suggested that hollow spindle ferric oxide (Hs-Fe 2 O 3 ) held good electrocatalytic activity toward H 2 S, which mainly depended on the coupling effect of Fe (III)/Fe (II) significantly reduced the overpotential of electro-oxidation reaction of H 2 S. 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 Fe 2 O 3 /CCB), low detection limit (1.86 μM), wide linear range (7.6~152 μM) and favorable selectivity. Furthermore, quantitative detection of H 2 S was achieved in fetal bovine serum samples, which confirmed that the sensor could become a promising strategy for detecting H 2 S in the pathological study of related diseases.