ortho-Phenylenediamine: an effective spacer to build highly magnetic Fe3O4/Au nanocomposites.

Graphical Link up: ortho -Phenylenediamine (PDA) acts as a linker in the deposition of gold nanoparticles on the surfaces of Fe 3 O 4 microspheres. After coating with PDA, the morphology of the microspheres changes significantly to nanoparticle clusters, and this is ideal for the deposition of the gold nanoparticles. The resulting Fe 3 O 4 /Au nanocomposites exhibit enhanced magnetism so that they can be recovered and recycled easily. 1,2-Diaminobenzene, popularly known as ortho -phenylenediamine (PDA), is found to be a prototype spacer for the deposition of gold nanoparticles on the surfaces of Fe 3 O 4 microspheres. Upon carbonization with PDA, the morphology of the product changes significantly, and the resulting nanocomposites exhibit enhanced magnetism beyond the saturation value of Fe 3 O 4 . The Fe 3 O 4 /Au nanocomposites show good surface-enhanced Raman spectroscopy activity with a detection limit of 10 −15 M .