Tailored synthesis of well-faceted single crystals of Fe3O4 and their application in p-nitrophenol reduction†
Abstract
Well-defined Fe3O4 nanocrystals (NCs), which exhibit excellent catalytic properties, have been synthesized in high yield via a facile hydrothermal method. Both the type of hydramine and concentration of NaOH play important roles in the formation of the Fe3O4 NCs with various morphologies. Detailed investigations indicated that the cubic and polyhedral Fe3O4 NCs can be prepared by adjusting the concentration of the triethanolamine (TEOA) in solution. The addition of increasing amounts of NaOH was found to facilitate the morphology transition from Fe3O4 cube shape to octahedron shape. The catalytic performances of these prepared samples have been investigated by reducing p-nitrophenol into p-aminophenol by an excess of N2H4 without the assistance of noble metals. The kinetics of the reduction reaction at different temperatures was also investigated to determine the activation parameters. Importantly, the obtained (100) faceted Fe3O4 nanocubes exhibits significantly higher catalytic activities than (111) faceted Fe3O4 octahedrons and bulk Fe3O4 nanoparticles, and these catalysts are stable and can be easily recycled.