Structural effects of Fe3O4 nanocrystals on peroxidase-like activity.

The catalytic activity of nanocrystal catalysts depends strongly on their structures. Herein, we report three distinct structures of Fe(3)O(4) nanocrystals, cluster spheres, octahedra, and triangular plates, prepared by a similar hydrothermal procedure. Additionally, the three Fe(3)O(4) nanostructures were used as peroxidase nanomimetics and the correlation between the catalytic activities and the structures was first explored by using 3,3',5,5'-tetramethylbenzidine and H(2)O(2) as peroxidase substrates. The results showed that the peroxidase-like activities of the Fe(3)O(4) nanocrystals were structure dependent and followed the order cluster spheres>triangular plates>octahedra; this order was closely related to their preferential exposure of catalytically active iron atoms or crystal planes. Such investigation is of great significance for peroxidase nanomimetics with enhanced activity and utilization.