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

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/NiOx@NF, prepared by in situ self-assembly of 3D hierarchical Co-Fe-Ni mixed oxides on nickel foam. The Co/Fe/NiOx@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 mu M. 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/NiOx@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/NiOx@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.