Iron single-atom anchored N-doped carbon as a ‘laccase-like’ nanozyme for the degradation and detection of phenolic pollutants and adrenaline

To solve the inherent defects of laccase, the first iron single-atom anchored N-doped carbon material (Fe1@CN-20) as a laccase mimic was disclosed. The FeN4 structure of this material can well mimic the catalytic activity of laccase. Although Fe1@CN-20 has a lower metal content (2.9 wt%) than any previously reported laccase mimics, it exhibits kinetic constants comparable to those of laccase, as its Km (Michaelis constant) and Vmax (maximum rate) are 0.070 mM and 2.25 µM/min respectively, which are similar to those of laccase (0.078 mM, 2.49 µM/min). This catalyst displays excellent stability even under extreme pH (2–9), high temperature (100 °C), strong ionic strength (500 mM of NaCl), high ethanol concentration (volume ratio 40%) and long storage time (2 months). Additionally, it can be reused for at least 7 times with only a slight loss in activity. Therefore, this material has a much lower price and better stability and recyclability than laccase, which has been applied in the detection and degradation of a series of phenolic compounds. In the detection of adrenaline, Fe1@CN-20 achieved a detection limit of 1.3 µM, indicating it is more sensitive than laccase (3.9 µM).