Constructing cobalt-based heterogeneous composites in porous charge transfer network enabled by the spiral structure for efficient detection of Cd2+ and Pb2+

Herein, a porous conductive network is constructed utilizing carbon nanocoils (CNCs) featuring a spatial helical structure. By integrating the continuous wet chemical method with an annealing process, cobalt-based composites derived from ZIF-67 are uniformly dispersed within this three-dimensional network. Three-dimensional carbonaceous nanomaterials represent a promising platform for the detection of heavy metal ions (HMIs). For simultaneous detection, the sensitivities for Cd 2+ and Pb 2+ were 9.816 and 13.950 µA µM −1 , respectively. The limit of detections for Cd 2+ and Pb 2+ were determined to be 1.11 and 0.93 nM, respectively. Using one-dimensional carbon nanotubes and two-dimensional reduced graphene oxide as the control group, it is evident that CNCs possess not only abundant micropores, which provide a wealth of active sites for charge accumulation in electrode materials, but also exhibit spatially ordered porosity. This structure includes macropores that serve as “warehouses” for electrolyte ions and mesopores that facilitate rapid electrolyte ion transfer. Furthermore, by integrating the proposed electrode with machine learning techniques, the classification accuracy can be significantly improved, achieving precision rates of 100 % and 92.86 %. This study proposes an effective strategy and introduces an innovative platform for developing electrochemical sensors designed to detect HMIs at trace levels.