Synthesis of metal-free nitrogen-enriched porous carbon and its electrochemical sensing behavior for the highly sensitive detection of dopamine: Both experimental and theoretical investigation

In this study, a nitrogen-inherited foam-like porous carbon was sequestered from the starch of Artocarpus heterophyllus seeds. The obtained carbon material was used as a sustainable electrode for the electrochemical detection of dopamine biomolecule. The material exhibited a turbostratic structure, high degree of graphitization, strong carbon-nitrogen bonding, high surface area, and porous architecture. It showed good catalytic activity with a low onset potential (80 mV), wide linear responses (30–90 μM and 200–400 μM), a low limit of detection (2.74 nM), and superior sensitivity (4.64 μA μM −1cm −2). The results indicated that the porous architecture and organic functionalities on the surface provided fast electron transfer at the electrode/electrolyte interface. Moreover, it offered superior stability, reproducibility, and biocompatibility toward dopamine sensing in real samples. Furthermore, first-principle calculations were performed in both the gas and aqueous phase to determine the molecular-level interaction between the porous carbon and dopamine. The results indicated that the interaction between dopamine and the nitrogen-enriched carbon sheet was stronger (−0.64 eV) than the oxygen-rich sheet. The atoms-in-molecules analysis, charge density difference analysis, and Fukui function plots indicated a charge transfer from the biomolecules to the carbon sheet. Overall, the theoretical findings confirmed the observed experimental results. [Display omitted] •The nitrogen-inherited foam-like porous carbon is sequestered from the starch of Artocarpus heterophyllus seeds.•It exhibits a turbostratic structure, high degree of graphitization, with porous architecture for dopamine sensing.•It showed good catalytic activity with a low limit of detection (2.74 nM), and superior sensitivity (4.64 μA μM −1cm −2).•The first-principle calculations used to determine the molecular-level interaction between the porous carbon and dopamine.•The interaction between dopamine and the nitrogen-enriched carbon sheet was stronger than the oxygen-rich sheet.