Encapsulation of Co3O4 Nanoparticles Inside CeO2 Nanotubes: An Efficient Biocatalyst for the Ultrasensitive Detection of Ascorbic Acid

A quick and sensitive detection of ascorbic acid (AA) is essential in the fields of biosensing and disease diagnosis. In this work, an effective approach combined with electrospinning, chemical bath deposition, and calcination process is developed to encapsulate Co 3 O 4 nanoparticle into CeO 2 nanotubes as efficient peroxidase mimics for the detection of AA. The peroxidase-like catalytic activity of the as-prepared Co 3 O 4 @CeO 2 nanotubes is much higher than that of individual Co 3 O 4 nanofibers and CeO 2 nanotubes alone due to the synergistic effect between the two components. Owing to the superior catalytic efficiency of the prepared Co 3 O 4 @CeO 2 nanotubes, a colorimetric route for the rapid and accurate detection of AA with a detection limit of 0.73 × 10 −9 m with a wide linear range from 0 to 0.8 × 10 −6 m is demonstrated. This detection limit is much better than the previous reports based on the enzyme-like catalytic systems. In addition, a good selectivity toward the detection of AA over amino acids, common ions, dopamine, and uric acid is achieved. This study offers a new approach for the fabrication of Co 3 O 4 @CeO 2 nanotubes as sensing platform toward the detection of AA, which presents promising potential applications in biosensing, environmental monitoring, and medical diagnostics.