Morphology-controlled electrochemical sensing properties of CuS crystals for tartrazine and sunset yellow

In this work, we demonstrate the morphology-controllable syntheses of CuS crystals by a facile hydrothermal/solvothermal method through merely changing the reaction solvents without employing any surfactants, templates or structure-directing agents. The dependence of electrochemical sensing properties for tartrazine (TT) and sunset yellow (SY) on the morphologies of CuS crystals (microspheres, hexagonal microsheets, sandwich-like plates, interlaced nanosheets and nanoflowers) was studied by voltammetric techniques. Among these CuS structures, the CuS nanoflowers constructed by textile-like nanosheets with a three-dimensional (3D) hierarchical porous structure hold the largest Brunauer-Emmett-Teller specific surface area (37.12 m(2) g(-1)) and display the highest electrocatalytic activities to the TT and SY oxidations. Consequently, the CuS nanoflowers modified electrode exhibits outstanding electrochemical sensing performances, i.e. high sensitivities of 1.7331 and 0.2260 A M-1 for TT, and 0.4228 and 0.01564 A M-1 for SY, low detection limits of 0.012 mu M for TT and 0.006 mu M for SY, and satisfactory recoveries of 97.0-104.5% for TT and 99.0-105.0% for SY. Simultaneously, it also features excellent anti-interference, stability and reproducibility. The superior sensing performance of CuS nanoflowers may benefit from its unique 3D hierarchical porous architecture, which can facilitate the electrolyte infiltration and promote the active material utilization efficiency. Based on these findings, we can draw a reasonable conclusion that CuS with a flower-like structure is promising electrocatalysts for efficiently sensing TT and SY.