Synergistic coupling of NiCo2O4 nanorods onto porous Co3O4 nanosheet surface for tri-functional glucose, hydrogen-peroxide sensors and supercapacitor

Abstract

Spinel-oxide-based mixtures have been explored for rapid and efficient biological molecule detection and energy storage applications. Porous Co3O4 nanosheets were used as growth sites, where NiCo2O4 nanorods were anchored to the Co3O4 surface to form porous Co3O4–NiCo2O4 nanosheets to achieve accurate glucose or hydrogen-peroxide monitoring and potential supercapacitor applications. The nanostructure and composition were confirmed by scanning-electron microscopy, transmission-electron microscopy and X-ray photoelectron spectroscopy. Under optimal preparation and sensing conditions, porous Co3O4–NiCo2O4 nanosheets exhibited a preeminent sensitivity towards glucose oxidation (1463.13 μA mM−1cm−2) and hydrogen-peroxide reduction (303.42 μA mM−1cm−2), with a low detection limit of 0.112 μM and 0.596 μM, respectively, and a good selectivity and reproducibility. Such porous mixture-coated Ni foam electrodes are suitable for supercapacitor performances with a high specific capacitance of 1041.2 F/g at a current density of 2 A/g and no obvious capacitance attenuation after 5000 cycles at a current density of 5 A/g, which will promote the exploration of nanocomposites in multi-purpose fields.