Reusable nickel foam supported 3D hierarchical Co–Fe–Ni mixed metal oxides with peroxidase-like activity as biosensors for the colorimetric detection of H2O2

Abstract

Nanomaterials with peroxidase-like activity have shown potential for hydrogen peroxide (H₂O₂) detection. However, the difficult separation and poor reusability of nanoparticles have hindered their further applications. Herein, we report a novel reusable peroxidase mimic, Co/Fe/NiO_x@NF, prepared by in situ self-assembly of 3D hierarchical Co–Fe–Ni mixed oxides on nickel foam. The Co/Fe/NiO_x@NF exhibited peroxidase-like activity, and we constructed a simple and convenient colorimetric sensing platform for H₂O₂ detection. The sensing platform displayed good linearity with a H₂O₂ concentration ranging from 0.2 to 4 mM and a low detection limit of 32.9 μM. We also applied the platform for the detection of H₂O₂ in actual samples and obtained satisfactory results. Due to the ferromagnetic properties and macro three-dimensional size of nickel foam, Co/Fe/NiO_x@NF can be easily recycled using a magnet or tweezers, eliminating the need for high-speed centrifugation as in typical nanozyme systems. Furthermore, the catalytic activity of Co/Fe/NiO_x@NF remained stable after one hundred successive cycles, demonstrating its potential for reuse. This feature reduces waste and cost and makes it an environmentally friendly and efficient method for H₂O₂ detection.