Carbon aerogels with nickel@N-doped carbon core-shell nanoclusters as electrochemical sensors for simultaneous determination of hydroquinone and catechol

Abstract

Rational design of carbon nanomaterials with high adsorption capability and remarkable catalytic activity is essential to achieve high-performance sensors. In this paper, supramolecular hydrogels cross-linking of Ni2+, chitosan (CS) and multi-walled carbon nanotubes (MWCNT) are prepared and used as the precursors to produce nanocomposites composed of core-shell structures and carbon aerogels (denoted as NCACNT/Ni) by facile pyrolysis. Due to the anchoring of abundant functional groups on the CS chains and the spatial confinement of MWCNTs, the N-doped carbon shells encapsulating Ni nanoclusters with the small size of ca. 4 nm uniformly distribute in the carbon aerogels. On one hand, the N atoms on the shell accepting electrons from Ni cores can easily adsorb hydroquinone and catechol (HQ and CT) by hydrogen bonding to enhance the local molecular concentration; on the other hand, the highly active NiNx sites can enhance the oxide current response signal. The high adsorption capability and remarkable catalytic activity endow the NCACNT/Ni with high performance towards qualitative and quantitative determination of HQ and CT with a linear range from 2 to 100 μM and respective limit of detection (LODs) of 0.36 μM (3σ/k) and 0.41 μM (3σ/k). This work paves a new pathway for the rational design and engineering of carbon nanomaterials for electrochemical sensors and environmental analyses.