Novel ZIF-67-derived Co3O4 hollow nanocages as efficient nanozymes with intrinsic dual enzyme-mimicking activities for colorimetric sensing

Nanozymes with multifaceted functionalities have accrued substantial interest as they provide an expanded spectrum of applications in comparison to their single-active nanozymes. In this endeavor, novel Co₃O₄ hollow nanocages (COHNs) derived from ZIF-67 were crafted adorned with the exceptional quality of dual-enzymatic prowess by employing a simple co-precipitation and pyrolysis technique, all the while meticulously exploring the intricacies of the catalyst mechanism. Kinetic analyses ascertained that the catalytic behavior of COHNs adhered to the archetypal dynamics of Michaelis–Menten, displaying a higher affinity for 3,3′,5,5′-tetramethylbenzidine (TMB) compared to natural enzymes. Leveraging the exceptional peroxidase- and oxidase-mimicking activity of the COHNs, a visual colorimetric assay platform was established for the detection of H₂O₂, ascorbic acid (AA), and acid phosphatase (ACP), all of which showed high selectivity and good sensitivity. Significantly, by harnessing the enzyme mimic property of COHNs, quantitative detection of H₂O₂, AA, and ACP unveiled astoundingly low detection limits of 0.0046 µM, 0.15 µM, and 0.0068 mU∙mL⁻¹, respectively. Moreover, the successful detection application in real samples attested to the superior stability and anti-interference ability of the colorimetric sensing system. This study not only provides a novel nanozyme boasting remarkably dual-enzymatic prowess, but also pioneers a rapid and sensitive method for environmental analysis and clinical diagnosis.

Graphical Abstract