Vertical α-FeOOH nanowires grown on the carbon fiber paper as a free-standing electrode for sensitive H₂O₂ detection

Highly sensitive, selective, and stable hydrogen peroxide (H₂O₂) detection using nanozyme-based catalysts are desirable for practical applications. Herein, vertical α-FeOOH nanowires were successfully grown on the surface of carbon fiber paper (CFP) via a low-temperature hydrothermal procedure. The formation of vertical α-FeOOH nanowires is ascribed to the structure-directing role of sodium dodecyl sulfate. The resulting free-standing electrode with one-dimensional (1D) nanowires offers oriented channels for fast charge transfer, excellent electrical contact between the electrocatalyst and the current collector, and good mechanical stability and reproducibility. Thus, it can serve as an efficient electrocatalyst for the reduction and sensitive detection of H₂O₂. The relation of the oxidation current of H₂O₂ with the concentration is linear from 0.05 to 0.5 mM with a sensitivity of -0.194 mA/(mM·cm²) and a low detection limit of 18 μM. Furthermore, the portability in the geometric tailor and easy device fabrication allow extending the general applicability of this free-standing electrode to chemical and biological sensors.