Soft template induced phase selective synthesis of Fe2O3 nanomagnets: one step towards peroxidase-mimic activity allowing colorimetric sensing of thioglycolic acid

Abstract

Different Schiff's base (SB) templates have been obtained to mediate phase selective synthesis of α- or γ-Fe₂O₃ from the same temperature condition. The inherent phase transformation tendency (γ-Fe₂O₃ to α-Fe₂O₃) is found to be inhibited. Again, the phase selective evolution emerges out of the binding modes of SBs which has been illustrated here. The nature of SBs governs the shape and size distribution of Fe₂O₃ NPs. As both the phases are magenetically active, easy magnetic separation of them widens their applicability in catalysis. Magnetically active both α- and γ-Fe₂O₃ mimic interesting peroxidase like activity by oxidising colourless 3,3′,5,5′-tetramethylbenzidine (TMB) to blue coloured oxidised product (Ox-TMB) in aqueous H₂O₂. These results prompted us to improvise further to detect thioglycolic acid (TGA) at a micromolar level which provides commercial applicability.