Influence of the hydrodynamic size and ζ potential of manganese ferrite nanozymes as peroxidase-mimicking catalysts at pH 4 in different buffers

Peroxidase-mimicking activity of manganese ferrite nanoparticles was studied, based on the oxidation TMB (3,3′,5,5′-tetramethylbenzidine) by H2O2 at pH 4 using acetate and citrate buffers. The aim this study to examine reaction not only enzymology (Michaelis-Menten kinetics model) but also surface science methods heterogeneous catalysis. Nanoparticles were characterized different techniques determine their phase composition, area, charge, point zero magnetization, mean size, morphology. Results show that nanozymes are coated with buffer anions form a shell around them. In addition, hydrodynamic size ζ potential under conditions play an important role in proposed Fenton-type mechanism. A greater amount Mn ions than Fe leaches from during oxidation, likely because is better protected coating outer nanoparticles. This shortcoming must be addressed when applying these nanomaterials.