A highly efficient NiCo 2 O 4 decorated g-C 3 N 4 nanocomposite for screen-printed carbon electrode based electrochemical sensing and adsorptive removal of fast green dye.

Herein, we demonstrate the preparation and application of NiCo2 O4 decorated over a g-C3 N4 -based novel nanocomposite (NiCo2 O4 @g-C3 N4 ). The prepared material was well characterized through several physicochemical techniques, including FT-IR, XRD, SEM, and TEM. The electrochemical characterizations via electrochemical impedance spectroscopy show the low electron transfer resistance of NiCo2 O4 @g-C3 N4 owing to the successful incorporation of NiCo2 O4 nanoparticles on the sheets of g-C3 N4 . NiCo2 O4 @g-C3 N4 nanocomposite was employed in the fabrication of a screen-printed carbon electrode-based innovative electrochemical sensing platform and the adsorptive removal of a food dye, i.e., fast green FCF dye (FGD). The electrochemical oxidation of FGD at the developed NiCo2 O4 @g-C3 N4 nanocomposite modified screen-printed carbon electrode (NiCo2 O4 @g-C3 N4 /SPCE) was observed at an oxidation potential of 0.65 V. A wide dual calibration range for electrochemical determination of FGD was successfully established at the prepared sensing platform, showing an excellent LOD of 0.13 µM and sensitivity of 0.6912 µA.µM-1 .cm-2 through differential pulse voltammetry. Further, adsorbent dose, pH, contact time, and temperature were optimized to study the adsorption phenomena. The adsorption thermodynamics, isotherm, and kinetics were also investigated for efficient removal of FGD at NiCo2 O4 @g-C3 N4 -based adsorbents. The adsorption phenomenon of FGD on NiCo2 O4 @g-C3 N4 was best fitted (R2  = 0.99) with the Langmuir and Henry model, and the corresponding value of Langmuir adsorption efficiency (qm ) was 3.72 mg/g for the removal of FGD. The reaction kinetics for adsorption phenomenon were observed to be pseudo-second order. The sensitive analysis of FGD in a real sample was also studied.