A simple 'in situ' co-precipitation method for the preparation of multifunctional CoFe2O4-reduced graphene oxide nanocomposites: excellent microwave absorber and highly efficient magnetically separable recyclable photocatalyst for dye degradation

Here, an 'in situ' co-precipitation reaction method has been reported for the preparation of CoFe2O4-RGO (CF-RGO) nanocomposites. To the best of our knowledge, this is the first time a simple synthetic method is reported for the preparation of CoFe2O4-RGO nanocomposites where a hydrothermal technique was not used. The novelty of this technique lies in its simplicity, cost-effectiveness, and the capability of large scale production of CoFe2O4-RGO nanocomposites. The synthesized CoFe2O4-RGO nanocomposites possess excellent microwave absorbing properties as well as high photocatalytic activity towards the degradation of various dyes under visible light irradiation. 85CF-15RGO (85 wt% CF and 15 wt% RGO) showed excellent microwave absorption properties with a Reflection Loss (RL) of similar to 31.31 dB (similar to 99.94% absorption) at 9.05 GHz with an 8.2-10.92 GHz effective band width range. To the best of our knowledge 85CF-15RGO nanocomposite exhibited comparable and even superior microwave absorption properties in the X-band region than most of the ferrite based composites. 75CF-25RGO (75 wt% CF and 25 wt% RGO) acted as a very good magnetically separable photocatalyst for the degradation of various synthetic dyes (such as methyl orange, methylene blue, rhodamine B and a mixture of these dyes) under visible light irradiation emitted from a 100 W reading lamp. Moreover, CoFe2O4-RGO catalyst also showed easy magnetic separation with high reusability. The photocatalytic activity of 75CF-25RGO was found to be comparable and in some cases better than the various reported RGO-ferrite composites. The simple method of preparation and multifunctional character make CF-RGO nanocomposites attractive materials for application in the area of photocatalysis as well as microwave absorption.