Oxygen vacancies modulation Se-doped ZnMn2O4/NC with high oxidase-mimicking activity for tetracycline hydrochloride detection

Convenient and reliable tetracycline hydrochloride (TC) detection is necessary due to its harmfulness. Herein, Se-doped ZnMn 2 O 4 /nitrogen carbon (NC) catalyst was effectively synthesized through step-by-step calcination in an N 2 atmosphere, which possessed enhanced oxidase mimetic activity. After Se doping, the oxidase-like activity of the catalyst is 2.75-fold and 1.64-fold higher than that of the Zn-Mn ZIF precursor and ZnO/MnO/NC, respectively. The Michaelis–Menten constant for Se-doped ZnMn 2 O 4 /NC with TMB substrate is 0.047 mM, which has higher affinity towards TMB than other manganese-containing materials. More oxygen vacancy in Se-doped ZnMn 2 O 4 /NC was recognized as the main sites for activating oxygen to produce reactive oxygen species to oxidize TMB. Based on the inhibitory effect of TC on the colorimetric system of TMB/Se-doped ZnMn 2 O 4 /NC, a simple method for TC detection was proposed with a wide linear range of 2–100 µM and 100–500 µM and a low detection limit of 0.88 µM. The method exhibited good selectivity to TC among some ions and antibiotics, and TC in the practical water samples was successfully detected.