Citrate Stabilized Au-FexOy Nanocomposites for Variable Exchange Bias, Catalytic Properties and Reversible Interaction with Doxorubicin

摘要

Exchange bias effect in Au-FexOy nanocomposites, prepared with regulated Au:Fe content, has been controlled using the variable iron content and the composition of FexOy. A green synthetic route has been adapted at room temperature in aqueous medium for such Au-Fe oxide nanocomposites. Diversity in FexOy compositions has been achieved through Au(III) reduction by Fe powder to obtain Au-FexOy nanocomposites in presence of gold nanoparticles as seed and threshold amount of sodium citrate as stabilizing agent. The exchange bias effect in selective Au-FexOy nanocomposites (5Fe, 6Fe, 7Fe and 9Fe) arises from the ferromagnetic-antiferromagnetic (FM-AFM) interaction between Fe3O4 and alpha-Fe2O3 present in the samples. A theoretical model is used to explain the variation of the exchange bias, coercivity and magnetization for the different samples at various temperatures. These Au-FexOy nanocomposites have been compared in terms of their catalytic activities for nitroarene reductions and reversible surface interaction with cancer drug doxorubicin.