FeVO₄/reduced graphene oxide: a novel robust peroxidase nanozyme. Application to fabricate an electrochemical glucose...

Herein, a FeVO₄/reduced graphene oxide (FeVO₄/rGO) nanocomposite was synthesized via a surfactant-assisted hydrothermal method and applied as a bifunctional platform for non-enzymatic H₂O₂ sensing and substrate-competitive enzymatic glucose detection. In this synthesis, sodium dodecylbenzene sulfonate (SDBS) acted as a structure-directing agent to facilitate the uniform distribution of FeVO₄ nanocrystals on the rGO network, thereby minimizing restacking and increasing the electroactive surface area. As a peroxidase-mimicking nanozyme, the FeVO₄/rGO composite enabled the sensitive detection of H₂O₂ via a hydroxyl radical-mediated electro-reduction mechanism. Michaelis-Menten kinetic analysis yielded a low Michaelis constant (K _m) of 0.176 mM and I _max of 52.66 µA, indicating high substrate affinity and catalytic efficiency. Based on this activity, the H₂O₂ sensor achieved a low limit of detection (LOD) of 0.15 µM, and high sensitivity (2560 µA mM^-1 cm^-2). Furthermore, a highly efficient cathodic glucose biosensor was fabricated by immobilizing glucose oxidase (GOx) onto the FeVO₄/rGO's surface. This bio-hybrid platform demonstrated high performance, achieving a linear concentration range from 0.05 to 1.0 mM with a remarkably low LOD of 0.06 µM and a sensitivity of 89.08 µA mM^-1 cm^-2. The glucose sensor displayed stability and selectivity against common interferents, and their practical applicability was validated in human urine samples. These results indicate that FeVO₄/rGO is a potential material for the development of clinical diagnostic devices.