Template synthesis of CoFe2O4 extended surface microspheres for efficient water decontamination and absorption of electromagnetic waves: Twin behavior

Achieving optimal morphologies specific for applications continues to be a challenge in the case of mesoporous ceramic oxide materials. It is well known that for several applications, nanograins need to remain un-agglomerated; this is because such particles offer larger specific surface. Here a novel template, economic route has been used for the synthesis of magnetic cobalt iron oxide with a hierarchical (and hence extended surface) morphology. These microspheres exhibit a high surface area of 786 m2 g−1 with large pore density. The particles are found to be excellent adsorbents and catalysts for oxidative-dissociation of Rhodamine B (RhB) and 4-Nitrophenol (4-NP) from water at room temperature. We also report the microwave absorbing capabilities of these materials, in the frequency range 1 MHz to 3 GHz. Interestingly these extended surface microspheres possess fine absorption of microwaves with two broad reflection loss peaks at −59 dB and −49.85 dB in the entire range. This is substantially different from the smooth surface cobalt ferrite that possesses only one absorption peak (−41.9 dB) in the low frequency region. Hence the reported material has plausible applications as magnetic adsorbents for pollution abatement, and also as electromagnetic shields.