Magnetic-field induced formation of 1D Fe₃O₄/C/CdS coaxial nanochains as highly efficient and reusable photocatalysts for water treatment

We report a novel strategy for fabrication of one-dimensional (1D) Fe ₃O₄/C/CdS coaxial nanochains via a magnetic field-induced assembly and microwave-assisted deposition method. First, 1D pearl chain-like Fe₃O₄/C core-shell nanocables are successfully assembled via the hydrothermal reaction of Fe₃O₄ nanospheres and glucose in water in the presence of an external magnetic field. The carbonaceous layer is about 10 nm in thickness, and it acts as the stabilizer for the Fe₃O₄ nanochains. Afterwards, CdS nanoparticles are facilely deposited onto the 1D Fe₃O₄/C nanochains via a rapid microwave-irradiation route to form 1D Fe₃O₄/C/CdS coaxial nanochains. Further investigation has revealed that these magnetic nanocomposites possess significantly improved activity as a recyclable photocatalyst for the degradation of organic pollutants when exposed to visible light irradiation. This new synthesis strategy is not restricted to the specific material discussed in this work and should be versatile for a wide range of magnetically separable photocatalysts containing 1D magnetic nanochains as the support and an outer layer of active semiconductor nanocrystals. © 2011 The Royal Society of Chemistry.