Synthesis of dopamine-derived N-doped carbon nanotubes/Fe₃O₄ composites as enhanced electrochemical sensing platforms for hydrogen peroxide detection

A novel preparation of dopamine-derived N-doped carbon nanotubes/Fe₃O₄ composites (N-CNTs/Fe₃O₄ Cs) is demonstrated via facile hydrothermal route and calcination treatment. In this approach, dopamine was selected as N-containing precursor, which can promote Fe₃O₄ nanocrystal deposition uniformly on the surface of CNTs and effectively modulated the graphitic structure with doped pyridinic N and graphitic N to improve the electrochemical performance of carbon composites. More interestingly, the inhibited growth of the Fe₃O₄ crystal during calcination can be effectively avoided by soaking PDA-CNT/Fe₃O₄ Cs in a phosphate solution before calcination. The N-CNTs/Fe₃O₄ Cs have an enhanced electrocatalytic activity toward hydrogen peroxide with high sensitivity (316.27 mA M⁻¹ cm⁻²) and wide linear range (0.006–2.057 mM). The N-CNTs/Fe₃O₄ Cs modified sensor was successfully applied to real-time detection of H₂O₂ released from living cancer cells, displaying a potential application in the study of oxidative stress-related diseases. This work demonstrates a rational way for high-performance electrocatalytic material synthesis and bioanalysis.