Evaluation of the synergistic effects of a novel organic-inorganic nickel hybrid nanocomposite as electrocatalyst toward glucose oxidation

A novel organic-inorganic hybrid nanocomposite obtained by electro-copolymerization of multi-walled carbon nanotubes and [Ni-(Protoporphyrin IX)], and then decorated with nickel metal nanoparticles (NiPPIX/CNT/NiNp) has been successfully prepared for its use in the non-enzymatic oxidation of glucose. The structural characterization and the electrochemical evaluation of the charge transport mechanisms for NiPPIX/NTC/NiNp were performed by SEM-EDX, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) measurements. The combination of two classes of electron hopping sites, nickel nanoparticles and the nickel atom of the porphyrin, embedded in an environment of high electronic delocalization and optimal film permeability, contributed to the electronic transfer processes, in terms of heterogeneous electron transfer rate constant (k° = 1.6 × 10−4 cm s−1 for NiPPIX/CNT/NiNp vs 2.4 × 10−5 cm s−1 for NiNp). NiPPIX/CNT/NiNp glassy carbon electrode shows the best linear response for glucose determination up to 6 mmol L−1, with a 0.9953 correlation coefficient and a slope of 0.2689 mA L mmol−1 cm−2. Lastly, the association of homogeneously distributed catalytic centers is an interesting strategy for the design of nanomaterials for sensing purposes. [Display omitted] •Novel organic-inorganic hybrid nanocomposite is applied to glucose electrooxidation.•Nickel nanoparticles and nickel center of porphyrin act as electron hopping sites.•Stable dispersion of carbon nanotubes in NiPPIX facilitates the electronic transfer.•Highest sensitivity (0.2689 mA L mmol−1 cm−2) is achieved with NiPPIX/CNT/NiNp.•The highest k°, 1.6 × 10−4 cm s−1, was obtained for NiPPIX/CNT/NiNp.