Facile fabrication and growth mechanism of 3D flower-like Fe3O4 nanostructures and their application as SERS substrates

Abstract

A template-free solvothermal combined with precursor thermal transformation method has been developed for the preparation of flower-like Fe 3 O 4 nanostructured hollow microspheres. The reaction mechanism and the self-assembly evolution process were studied, and it was found that the synthetic conditions for the precursor such as reaction time, urea concentration and non-aqueous media are all crucial for the formation of the flower-like hierarchical precursors. The flower-like Fe 3 O 4 microspheres obtained by calcining the precursor in Ar gas exhibit superparamagnetic behavior and show relative high saturation magnetization at room temperature. To endow them with SERS activity, silver coating was conducted by magnetron sputtering. The obtained Fe 3 O 4 /Ag hybrid microflowers make a positive influence on the high sensitivity of SERS to 4-pyridinethiol (4-Mpy) and Rhodamine 6G (R6G) molecules when compared with the silver film substrates. More importantly, the detection limit of Fe 3 O 4 /Ag hybrid microflowers for R6G dye can reach up to 10 215 M, which meets the requirements of ultratrace detection of analytes using SERS. Thus, the SERS-active magnetic hybrids prepared in this work may possibly be used as an optical probe with magnetic function for application in high-sensitivity bioassays.

Synthesis of V2O5 hierarchical structures for long cycle-life lithium-ion storage

“…Aer solvothermal treatment for 3 h (Fig. 40 Then the nanosheets assembled to form a ower-like hierarchical structure which may be caused by a combination of van der Waals forces, hydrogen bonds, and hydrophobic interactions in the solvothermal environment. With a reaction time of 9 h, well-dened ower-like hierarchical structures are produced, as shown in Fig.…”

Formation of Uniform FeP Hollow Microspheres Assembled by Nanosheets for Efficient Hydrogen Evolution Reaction

“…Moreover, the bands located at 1455 and 1630 cm −1 are due to COO − stretching bands . According to the above experimental results, it is further suggested that the as‐synthesized Fe‐precursor is Fe‐based glycolate, a complex containing ferrous ion, EG and OH group …”

Review on the Synthesis and Applications of Fe3O4 Nanomaterials

“…The possible formation mechanism is shown in Figure 4. [57], magnetic resonance contrast agent [73], catalyst [74,75], drug delivery [76], and magnetic resonance imaging (MRI) contrast agents [77].…”