Synthesis of 3D Hierarchical Fe₃O₄/Graphene Composites with High Lithium Storage Capacity and for Controlled Drug Delivery

Abstract

Three-dimensional (3D) hierarchical Fe 3 O 4 /graphene nanosheet (GNS) composites have been synthesized using a simple in situ hydrothermal method. Characterization shows that the Fe 3 O 4 nanoflowers are highly encapsulated in a GNS matrix. The Fe 3 O 4 /GNSs-1 nanocomposite (60 wt % of Fe 3 O 4 in the composites) exhibits a stable capacity of ∼605 mAh g –1 with no noticeable fading for up to 50 cycles in the voltage range of 0.001–3.0 V, and the superior performance of Fe 3 O 4 /GNSs-1 is clearly established by comparison of the results with those from Fe 3 O 4 /GNSs-2 (23 wt % of Fe 3 O 4 in the composites) and bare Fe 3 O 4 . In addition, another possible application of the drug delivery with the composites shows that the loading of rhodamine B (RB) on Fe 3 O 4 /GNSs increased linearly with the increase in the initial RB concentration, and the loading capacity of Fe 3 O 4 /GNSs-1 was as high as 3.18 mg mg –1 . The excellent electrochemical performance of the composites and highly efficient loading of RB could be attributed to the enhanced electronic conductivity and the large surface areas of the Fe 3 O 4 /GNSs in which the hierarchical structure of Fe 3 O 4 nanoflowers are highly encapsulated in the GNS matrix.