Synthesis of Fe 3 O 4 ‐Au Nanocomposites with Enhanced Peroxidase‐Like Activity

Sphere‐like Fe 3 O 4 aggregates were solvothermally prepared with ethylene glycol, sodium acetate and FeCl 3 · 6H 2 O as raw materials. The sphere‐like Fe 3 O 4 aggregates provided heterogeneous growth sites for Au nanoparticles. These were obtained by reduction of HAuCl 4 by sodium citrate under mild reaction conditions and the Fe 3 O 4 ‐Au nanocomposites were subsequently formed. The peroxidase‐like activity of nanocomposites was studied with H 2 O 2 and 3,3′,5,5′‐tetramethylbenzidine as substrates. Fe 3 O 4 ‐Au nanocomposites exhibited better catalytic activity than pure Fe 3 O 4 aggregates, mainly resulting from the special electronic structure at the interfaces between the sphere‐like Fe 3 O 4 aggregates and the gold nanoparticles.