Decoration of nanoporous stainless steel with nanostructured gold via galvanic replacement reaction and its application for electrochemical determination of dopamine

• Nanoporous stainless steel was decorated with Au (Au/NPSS) via galvanic replacement.
• Compared with a flat gold electrode, Au/NPSS showed a higher active surface area.
• Au/NPSS exhibited good electrocatalytic behavior for determination of dopamine.
• A linear range of 1.0–2000 μM and limit of detection of 0.02 μM were obtained.
• Common interfering species have no obvious effects on the determination of dopamine.

A stainless steel substrate with highly ordered self-organized nanopores was decorated with gold nanostructures (Au/NPSS) for use in electrochemical biosensors. The nanopores were formed on stainless steel surface using anodization process, filled with Cu using pulsed electrodeposition and followed by galvanic replacement of Cu with gold. The characteristics of the electrode and its potential application for electrochemical determination of dopamine (DA) were investigated using scanning electron microscopy, energy-dispersive X-ray spectroscopy, cyclic voltammetry and electrochemical impedance spectroscopy. The results indicated that compared to a smooth gold electrode, the nanostructured gold film formed on the NPSS has a great active surface area and displays a higher peak current for DA oxidation. Cyclic voltammetric determination of DA exhibited two wide linear ranges of 3.0–8.0 and 8.0–2000 μM with a detection limit of 0.07 μM (3Sb/m). Moreover, two lines in the range of 1.0–80.0 μM of DA with a limit of detection of 0.02 μM (3Sb/m) were obtained using differential pulse voltammetry. Au/NPSS exhibited good repeatability and reproducibility, long-term stability and acceptable selectivity. This work opens up new prospects for the fabrication of inexpensive noble metal-based catalysts supported on NPSS, which have a potential application in biosensors.

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