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