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

Duozhe Chen ^a, Di Pang ^a, Shupeng Zhang ^{a, c*}, Haiou Song ^b,*, Weiqing Zhu ^a, Junwu Zhu ^{a, c*}

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.