Impregnation of High-Magnetization FeCo Nanoparticles in Mesoporous Silicon: An Experimental Approach

Abstract

This paper deals with the synthesis of high-magnetization porous silicon-based nanocomposites. Using well-controlled organometallic synthesis of ferromagnetic FeCo nanoparticles, the impregnation of mesoporous silicon has been performed by immersion of porous silicon in a colloidal solution. The technique was optimized by controlling the temperature, the immersion duration, and the solvent nature. The characterization of the nanocomposites showed a homogeneous filling of the pores and a high magnetization of 135 emu/cm3. Such composites present a great interest for many applications including data storage, medical instrumentations, catalysis, or electronics.

Ultrastable Magnetic Nanoparticles Encapsulated in Carbon for Magnetically Induced Catalysis

“…The methodology to encapsulate MagNPs in carbon is based on a two-step procedure. FeCo prepared by a previously reported procedure , and Co nanoparticles prepared by adaptation of the same procedure (see Experimental Section, section 2) were supported on activated carbon (FeCo/C and Co/C; 5 wt %). The MagNPs were then encapsulated in carbon through a pyrolysis process (600 °C, 2 h, 10 °C/min) to afford FeCo and Co NPs covered by a narrow carbon layer (Figure ; FeCo@C and Co@C ).…”

“…To investigate in more detail the stability of our heating agents and of the catalyst under the harsh conditions employed, we ran PDR over 6 h. Specifically, we tested 2:1 FeCo@C:Co@C/Ni (10 wt % of Ni) and a gas mixture of 3:1 CO 2 :C 3 H 8 with a total flow rate of 10 mL min −1 during 6 h. We previously showed that after 2 h on stream, 52% yield could be reached with nearly 100% selectivity for CO, whereas supported Ni NPs were slightly agglomerated. Two more cycles with variable magnetic-field amplitudes (32,44,53, and 60 mT) were performed and enabled to show a quasi-perfect cyclability in terms of temperature reached by magnetic induction of the heating agents (up to 620 °C, at μ 0 H rms 60 mT, 300 kHz) and CO yields (Figure 8). This result demonstrates the very efficient encapsulation of the FeCo@C and Co@C even at high temperatures.…”

Controlled Drug Delivery Systems: Current Status and Future Directions

“…When they are administered, the drug release is activated and then modulated through some action or external input and facilitated by the energy supplied externally. The responsive delivery systems respond to external stimuli such as temperature [ 135 ], pH [ 136 ], solvent [ 137 ], ultrasound [ 138 ], electric field [ 139 ] and magnetic field [ 140 ]. The changes in network structure in response to the external environment are reversible [ 141 ].…”

Single-Crystalline Body Centered FeCo Nano-Octopods: From One-Pot Chemical Growth to a Complex 3D Magnetic Configuration

“…Previous reports have shown the potential interest of replacing oxides with materials exhibiting higher saturation magnetization values, such as metallic Fe, Co, or their alloys. , We have recently reported the synthesis of single-crystalline FeCo NPs following an organometallic approach . Their size, shape, and chemical composition could be tuned by the experimental parameters (nature and concentration of ligands, precursor concentrations). , As prepared, these NPs exhibited saturation magnetization values comparable with that of the bulk one ( M s = 226 A·m 2 ·kg –1 ). , …”

“…27,28 As prepared, these NPs exhibited saturation magnetization values comparable with that of the bulk one (M s = 226 A•m 2 •kg −1 ). 27,29 In this paper, we report the synthesis and the advanced magnetic characterization of FeCo nano-octopods. These single-crystalline bcc nanostars are enclosed by high-energy {311} facets as revealed by advanced electron microscopy techniques.…”