Trace Iodide Dramatically Accelerates the Peroxidase Activity of VOx at ppb-Concentration Levels

Despite artificial nanozymes, as compared to natural enzymes, exhibit distinct superiorities of low cost, robustness against harsh environments, high stability and easy mass-production, the relatively lower activity and efficiency still seriously restrict their application in high-performance photometric chemosensing and biosensing. Promoting the activity and efficiency of nanozymes turns to be a significant yet challenging goal of the nanozyme community. Here we found, for the first time, that trace I- can dramatically boost the peroxidase-like activity (over 50-fold higher) of VOx at ppb-concentration levels. It was deduced that the significant enhancement of nanozymatic activity mainly results from the synergetic modulation of surface redox and electronic structure of VOx. Based on this finding, ultrasensitive photometric detection of both H2O2 and I- (down to nM) was realized.