Fluoride capped V6O13–reduced graphene oxide nanocomposites: high activity oxidase mimetics and mechanism investigation

Abstract

Nanostructured artificial enzyme mimics (nanozymes) are promising frontiers and have received considerable attention in chemical research. However, the practical applications of nanozymes were severely hampered by their limited catalytic activity and overall catalytic efficiency, and the current reports indicated that quite rare vanadium oxides have oxidase activity. Herein, we demonstrated that fluoride capped V₆O₁₃–rGO nanocomposites exhibited high oxidase mimetic activity for the first time. The well fluoride capped V₆O₁₃–rGO nanocomposites obviously improved the catalytic activity and kinetic performance compared with V₆O₁₃ and V₆O₁₃–rGO. The V_max of V₆O₁₃–rGO in the presence of fluoride for TMB oxidation was 10⁻⁸ M s⁻¹, which was 2.8-fold higher than that of V₆O₁₃–rGO without fluoride, illustrating a better efficiency substrate uptake. The mechanism is attributed to the specific fluoride capping, which could change the surface charge of V₆O₁₃–rGO for improving the substrate adsorption affinity and enhancing the electron transfer rate. The prepared nanozyme exhibited excellent catalytic performance for the establishment of fluoride colorimetric sensors and detection of fluoride in tap water. The outcome indicated that the developed nanozyme could be extended to a broad range of practical applications in biotechnology, biocatalysis, and biomedical engineering.