Validation of synergistic effect in N[sbnd]C@SnO2 hollow nano-microspheres through interfacial chemical bonding for boosting electrochemical sensing.

[Display omitted] • Uniform double-shell N C@SnO 2 HNs were assembled by interfacial bonding. • Interface Sn-C bond was proved by XPS characterization and DFT calculation. • Sn-C synergistic effect promotes the electron transfer and electrochemical sensing. • Low LOD (41.5 nM) and wide detection range (0.5–25 μM) of DA were realized. • The portable microchip was developed in service to in-situ DA detection. Higher resistance is exceptionally detrimental to metal oxide-based electrochemical sensors' detection performances that depend on their electrical conductivity. Herein, guided by the synergistic effect of the heterophase boundary, a hollow core–shell combination with a double-layered structure was engineered via hydrolysis strategy, namely nitrogen-doped carbon hollow nano-microspheres (N C HNMs) coated with SnO 2 outer layer (N C@SnO 2 HNMs), then applied for high-performance electrochemical sensing. Advantages including large surface area and strong electronic coupling of Sn-C bond on the boundary facilitated the adsorption of target molecules and electron transferring across the composites, achieving efficient quantitative identification. Density functional theory (DFT) calculation demonstrated the motivation of the charge accumulation at the interface due to the formation of the Sn-C bond, which acted as a bridge for charge transfer. Unsurprisingly, the N C@SnO 2 HNMs-based electrode showed an excellent performance toward dopamine (DA), such as favorable DA selectivity, a lower limit of detection, and a wide linear detection range. Moreover, the electrode material could be applied to the microsensor for in-situ DA detection in artificial sweat. [ABSTRACT FROM AUTHOR]