Palygorskite@Co3O4 nanocomposites as efficient peroxidase mimics for colorimetric detection of H2O2 and ascorbic acid

Nanomaterials with intrinsic enzyme-like activities have attracted extensive research interest as promising alternatives to natural biological enzymes due to their advantages of low cost and high stability. Many artificial enzyme mimics have been successfully applied in the fields of sensing, environmental treatment, and oncotherapy. Herein, novel palygorskite@Co3O4 nanocomposites (Pal@Co3O4 NCs) were fabricated by modifying Pal with Co3O4 nanoparticles through a facile hydrothermal method. The obtained Pal@Co3O4 nanocomposites as nanozymes displayed enhanced peroxidase-like activity, which can catalyze the oxidation of 3,3,5,5-tetramethylbenzidine (TMB) in the presence of hydrogen peroxide (H2O2) to obtain colored products. Kinetic assay indicated that the Pal@Co3O4 peroxidase mimics showed a higher affinity towards TMB than that of natural horseradish peroxidase (HRP). Moreover, a sensitive and selective sensor for colorimetric determination of H2O2 and ascorbic acid (AA) was successfully constructed by using Pal@Co3O4 nanocomposites as peroxidase mimics. Furthermore, the proposed assay for sensing of AA in model samples was evaluated with satisfactory results, demonstrating the potential applications in complex biological systems. •Novel Pal@Co3O4 NCs were first fabricated through a facile hydrothermal method.•Pal@Co3O4 NCs showed enhanced peroxidase-like activity with a high affinity to TMB.•A colorimetric sensor for H2O2 and AA was developed using Pal@Co3O4 NCs as nanozymes.•The sensitive and selective sensor could be applied for AA detection in real samples.