Constructed ILs coated porous magnetic nickel cobaltate hexagonal nanoplates sensing materials for the simultaneous detection of cumulative toxic metals.

The different morphologies of magnetic nickel cobaltate (NiCo2 O4 ) electrocatalysts, consisting of nanoparticles (NiCo2 O4 -N), nanoplates (NiCo2 O4 -P) and microspheres (NiCo2 O4 -S) were fabricated. It was found that the electrocatalytic properties of the sensing materials were strongly dependent on morphology and specific surface area. The porous NiCo2 O4 hexagonal nanoplates coupled with ILs as modified materials (ILs@NiCo2 O4 -P) for the simultaneous determination of thallium (Tl+ ), lead (Pb2+ ) and copper (Cu2+ ), exhibited high sensitivity, long-time stability and good repeatability. The enhanced electrocatalytic activity was attributed to relatively large specific surface area, excellent electronic conductivity, and unique porous nanostructure. The analytical performance of the constructed electrode on detection of Tl+ , Pb2+ and Cu2+ was examined using differential pulse anodic stripping voltammetry (DPASV). Under optimal conditions, the electrode showed a good linear response to Tl+ , Pb2+ and Cu2+ in the concentration range of 0.1-100.0, 0.1-100.0 and 0.05-100.0μg/L, respectively. The detection limits (S/N=3) were 0.046, 0.034 and 0.029μg/L for Tl+ , Pb2+ and Cu2+ , respectively. The fabricated sensor was successfully applied to detect trace Tl+ , Pb2+ and Cu2+ in various water and soil samples with satisfactory results. Hence, this work provided a promising material for electrochemical determination of cumulative toxic metals individually and simultaneously.