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

Nanomaterials with peroxidase-like activity have shown potential for hydrogen peroxide (H 2 O 2 ) 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 H 2 O 2 detection. The sensing platform displayed good linearity with a H 2 O 2 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 H 2 O 2 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 H 2 O 2 detection. A fast visual sensing platform for H 2 O 2 was developed based on a novel recyclable nanozyme.