Peroxidase-mimetic activity of a nanozyme with uniformly dispersed FeO NPs supported by mesoporous graphitized carbon for determination of glucose.

A FeO/mesoporous graphitized carbon (FeO/m-GC) composite was prepared through a facile calcination method with iron-based metal-organic frameworks (Fe-MOFs) as a sacrificial template. After carbonization, the FeO nanoparticles were uniformly dispersed in the mesoporous carbon support, resulting in spatial structural stability. The mesoporous carbon support obtained was highly graphitized and exhibited eminent electrical conductivity, which accelerated the electron transfer between the FeO nanoparticles by Fe(II)/Fe(III) redox cycles and m-GC by C = C/C-C redox cycles, leading to the excellent peroxidase-mimetic activity of FeO/m-GC. K values for tetramethylbenzidine (TMB) and HO were 26.8 and 15.8 times lower than that of natural horseradish peroxidase, respectively. Taking advantage of the peroxidase-mimetic activity of FeO/m-GC, a colorimetric assay was fabricated for detecting glucose in the range 0.5 ~ 200 μM, with a limit of detection of 0.24 μM. Fig 1 A Schematic illustration of the preparation process of FeO/m-GC, B schematic illustration of a proposed synergistic catalytic mechanism of TMB oxidation by FeO/m-GC.