Vanadium doped ZIF-L derived V-NC peroxidase-like nanozymes for tannic acid sensing

Transition metal-based nitrogen doping carbon nanozyme has attracted great attention owning to their high potential to replace natural enzymes. In this study, we prepared novel vanadium doped ZIF-L derived N-doped carbon nanozyme (V-NC) via facilely pyrolysis strategy. The cross-shaped morphology endows V-NC with unique V-Nx active sites, hierarchical pore character and large specific surface area, leading to its good peroxidasemimetic activity. The steady-state kinetics trials revealed the low Km values of V-NC for TMB and H2O2, demonstrating its good affinity to TMB and H2O2. Mechanism research revealed that the excellent peroxidaselike activity of V-NC resulted from co-participation of center dot OH and O2 center dot- , which were confirmed by reactive oxygen species (ROS) scavenging experiments and EPR trials. Under optimized operational conditions, and by virtue of the antioxidant properties of tannic acid (TA), a colorimetric sensing assay based on the peroxidase-like activity of V-NC was developed for sensitive detection of TA in the 0.1-2.5 mu M linear range with low detection limit of 19.8 nM and the relative standard deviation (RSD, n = 3) of below 5%. This work renders a new idea for designing and developing high activity N-doped carbon nanozyme, and provides an accurate and feasible assay for the analysis of TA in real samples.