Sulfur-modified V₂O₅ nanozymes with altered ROS generation characteristics for enhanced glucose colorimetry

Area of Science:

• Nanomaterials Science
• Catalysis
• Surface Chemistry

Background:

• Defect and surface-chemistry regulation are key strategies for enhancing nanozyme performance and controlling reactive oxygen species (ROS) generation.
• The specific impact of sulfur modification on the surface oxygen environment and ROS generation in vanadium pentoxide (V2O5) nanozymes is not well understood.

Purpose of the Study:

• To investigate the relationship between sulfur-induced structural modification, surface oxygen environment, and ROS generation in V2O5 nanozymes.
• To evaluate the catalytic performance and sensing capabilities of sulfur-modified V2O5 (S-V2O5) nanozymes.

Main Methods:

• Preparation of S-V2O5 nanozymes via a precursor-transformation route involving sulfurization and air-oxidation reconstruction.
• Characterization of structural and surface properties using techniques like electron paramagnetic resonance (EPR).
• Assessment of peroxidase-like (POD-like) activity, substrate affinity, and ROS generation under TMB-H2O2 conditions.
• Development of a glucose oxidase (GOx)/S-V2O5 cascade system for glucose colorimetric detection.

Main Results:

• S-V2O5 nanozymes retained the V2O5 crystalline framework but exhibited local structural perturbations, altered surface oxygen, increased defects, and more reduced V species.
• Enhanced POD-like activity, improved substrate affinity, and good cycling stability were observed for S-V2O5 compared to pristine V2O5.
• Altered ROS generation characteristics were detected, with a more pronounced superoxide signal in S-V2O5, though multiple pathways may coexist.
• The GOx/S-V2O5 cascade system demonstrated sensitive and selective glucose colorimetric detection.

Conclusions:

• Sulfurization-oxidation reconstruction effectively modulates the local structure and surface chemistry of V-based oxide nanozymes.
• This modification enhances POD-like catalytic output and improves colorimetric sensing performance, particularly for glucose detection.
• The study highlights sulfur modification as a viable strategy for optimizing nanozyme functionality.