Influence of VO₂ Nanoparticle Morphology on the Colorimetric Assay of H₂O₂ and Glucose.

Nanozyme-based colorimetric sensors have received considerable attention due to their unique properties. The size, shape, and surface chemistry of these nanozymes could dramatically influence their sensing behaviors. Herein, a comparative study of VO₂ nanoparticles with different morphologies (nanofibers, nanosheets, and nanorods) was conducted and applied to the sensitive colorimetric detection of H₂O₂ and glucose. The peroxidase-like activities and mechanisms of VO₂ nanoparticles were analyzed. Among the VO₂ nanoparticles, VO₂ nanofibers exhibited the best peroxidase-like activity. Finally, a comparative quantitative detections of H₂O₂ and glucose were done on fiber, sheet, and rod nanoparticles. Under the optimal reaction conditions, the lower limit of detection (LOD) of the VO₂ nanofibers, nanosheets, and nanorods for H₂O₂ are found to be 0.018, 0.266, and 0.41 mM, respectively. The VO₂ nanofibers, nanosheets, and nanorods show the linear response for H₂O₂ from 0.025-10, 0.488-62.5, and 0.488-15.625 mM, respectively. The lower limit of detection (LOD) of the VO₂ nanofibers, nanosheets, and nanorods for glucose are found to be 0.009, 0.348, and 0.437 mM, respectively. The VO₂ nanofibers, nanosheets, and nanorods show the linear response for glucose from 0.01-10, 0.625-15, and 0.625-10 mM, respectively. The proposed work will contribute to the nanozyme-based colorimetric assay.