Self-assembly into magnetic Co 3 O 4 complex nanostructures as peroxidase

Here we reported on the synthesis and characterization of Co3O4 gillyflower-like nanostructures (termed as CGN) with peroxidase-like activity via an L-arginine-assisted hydrothermal synthesis approach. The CGN were characterized by a wide range of physicochemical characterization techniques. The temperature-dependence magnetic measurement (M–T) of the CGN shows a very low Néel temperature (TN) of 10.6 K, due to the finite-size scaling effect. The CGN catalysed the reaction of peroxidase substrate 3,3′,5,5′-tetramethylbenzidine (TMB) to give the same colour changes as horseradish peroxidase (HRP, the most commonly used catalyst in the enzymatic reaction). And the catalysis by CGN presented the typical Michaelis–Menten kinetics, and exhibited excellent catalytic efficiency. This study demonstrated that the CGN owns an intrinsic peroxidase-like activity.