Gold Embedded Maghemite Hybrid Nanowires and Their Gas Sensing Properties

Abstract

Well-defined gold embedded maghemite hybrid nanowires are synthesized, and their structures are fully characterized. They are composed of porous γ-Fe2O3 shells and embedded gold nanoparticles (3-10 nm), which is novel and very different from the conventional "surface decoration" configuration. These hybrid nanowires are produced by the de-alloying of Au-Fe alloy nanowires and subsequent heat treatment. The reaction mechanism is proposed and validated. The results of X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and thermogravimetry techniques prove consistently that the Fe composition of Au-Fe alloy nanowires change to γ-FeOOH first and then to γ-Fe2O3. The embedded gold particles are help to enhance the gas response properties of the hybrid nanowires, which is attributed to the nano open-circuit Schottky junctions between γ-Fe2O3 and the Au nanoparticles. The gas sensing experiment data with high repeatability demonstrate that these hybrid nanowires are excellent sensing materials, especially for ethanol, and have shown both high selectivity and high sensitivity.

Versatile design and synthesis of nano-barcodes

“…130,171,214 The synthesis of Sn-Ag, Sn-Pb, and Au-Fe alloy based nanowires has also been demonstrated. 10,215 Fig . 15 Strategy of surface decoration on preformed encoding carriers.…”

Gold Nanomaterials and Bone/Cartilage Tissue Engineering: Biomedical Applications and Molecular Mechanisms

“…For gold nanomaterials, AuNPs, as well as nanoclusters (AuNCs), nanocages, nanorods (AuNRs), nanobelts, nanoplates and so on, are becoming increasingly popular because of their optical nonlinearities (Gao et al, 2015;Huang et al, 2017;Zhang et al, 2018), local surface plasmon resonance (SPR) (Li Q. et al, 2017) and photothermal effect (Jiang et al, 2012). Considering these characteristics, it has been proved that gold nanomaterials can be used in many fields such as chemistry, biomedicine, including the diagnosis and treatment of diseases (Li et al, 2018b), sensor (Li et al, 2015), catalysis (Li et al, 2013), surface-enhanced Raman spectroscopy (Huang et al, 2019), illumination (Zhang et al, 2017b), detector (Du et al, 2018), and therapy (Yeh et al, 2012). The easy of synthesis and the unique properties of gold nanomaterials make them ideal candidates for translation from the laboratory scale into the clinical arena for use in humans.…”

One-Dimensional Plasmonic Sensors

“…Embedded with NPs, the gas response performance of MOS-based gas sensors is improved. The hybrid NWs with a wrinkled γ-Fe 2 O 3 outer shell and embedded Au NPs [56] exhibit excellent performance in ethanol sensing with high sensitivity and selectivity. Another NPs-decorated MOSs-based sensor [25] is presented for bio-sensing by Kim et al from Dankook University.…”