Surface nitrogen-enriched carbon nanotubes for uniform dispersion of platinum nanoparticles and their electrochemical biosensing property

• Pyrolysis of polydopamine-wrapped CNTs provides a generalized and robust way to prepare surface-nitrogen-enriched CNTs.
• Pt nanoparticles loaded on CNx-CNTs have a smaller particle size, better dispersion than that on nitrogen-free CNTs.
• The Pt/CNx-CNTs shows significantly enhanced electro-catalytic activity towards oxidation of H2O2.
• the Pt/CNx-CNTs is an electrode material in GOD amperometric biosensor with superior characteristics comparing with Pt/CNTs.

Nitrogen containing carbon layer-coated carbon nanotubes (CNx-CNTs) was prepared as the support for platinum nanoparticles (Pt NPs) and their enhanced properties for electrochemical biosensor has been demonstrated in this paper. The CNx-CNTs were obtained from pyrolysis of polydopamine-wrapped CNTs, which were synthesized by a single deposition process based on the oxidative self-polymerization of dopamine on CNTs. It is found that Pt NPs are deposited on the surface of the CNx-CNTs (Pt/CNx-CNTs) with highly dispersion and small particle size (with an average diameter of 1.7 ± 0.3 nm). Compared to the nitrogen-free CNTs supported Pt NP composite (Pt/CNTs), the Pt/CNx-CNTs modified glassy carbon (GC) electrode exhibits superior electrocatalytic performance towards the oxidation of hydrogen peroxide (increase by about 55% of response current). Taking glucose oxidase (GOD) as the model, the proposed amperometric enzyme biosensor based on the Pt/CNx-CNTs shows excellent analytical characteristics to glucose detection, such as excellent sustainability in large range of pH values, high sensitivity (66.51 μA (mmol dm−3)−1 cm−2), wide linear range (0.01-6.1 mmol dm−3) and low detection limit (0.4 μmol dm−3).

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