Hollow cobalt ferrite–polyaniline nanofibers as magnetically separable visible-light photocatalyst for photodegradation of methyl orange

Hollow cobalt ferrite–polyaniline nanofibers (CoFe 2 O 4 –PANI) functioning as a photocatalyst were prepared by using electrospinning technique, followed by calcination and in-situ chemical oxidative polymerization. The hollow CoFe 2 O 4 –PANI nanofibers with one dimensional (1D) structure provide well-developed mesoporous structure and enhanced electrical conductivity. The hollow CoFe 2 O 4 –PANI nanofibers consisted of hollow core-double shell nanostructure, which has CoFe 2 O 4 as inner shell and PANI as outer shell. The hollow CoFe 2 O 4 –PANI nanofibers coated with PANI nanograins facilitate the optical properties by easily capturing visible light. The intensive visible light absorption and effective charge separation lead to a remarkable improvement of visible light photocatalysis owing to the heterojunction built between CoFe 2 O 4 and PANI. The pseudo-first-order kinetic constant of photocatalytic degradation of the methyl orange (MO) dye under visible light irradiation with CoFe 2 O 4 –PANI was 80 times greater than CoFe 2 O 4 . This evidence shows the advantage of the unique core–shell mesoporous structure in the CoFe 2 O 4 –PANI for efficient photocatalysis. The recovery ratio is almost the same after three cycles under visible light irradiation, displaying the excellent characteristics of magnetic separation for CoFe 2 O 4 –PANI hollow nanofibers.