Hierarchical Fe3O4@TiO2 Yolk–Shell Microspheres with Enhanced Microwave‐Absorption Properties

Liu, Jiwei; Xu, Jingjun; Che, Renchao; Chen, Huajun; Liu, Mengmei; Liu, Zhengwang

doi:10.1002/chem.201203557

Cited by 202 publications

(113 citation statements)

References 47 publications

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“…[ 4,5 ] Among many kinds of microwave absorbers, carbon materials are always the most attractive candidates due to their tunable properties, relative low density, abundant resource, easy preparation, and low cost. Various carbon materials, e.g., carbon nanotubes (CNTs), carbon nanofi bers (CNF), carbon nanocoils, and mesoporous carbon, have been utilized to construct highly effective microwave absorbers in the past decades.…”

mentioning

confidence: 99%

Interfacially Engineered Sandwich‐Like rGO/Carbon Microspheres/rGO Composite as an Efficient and Durable Microwave Absorber

Wang

Qiang

et al. 2016

Adv Materials Inter

135

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EM pollution, because they can convert the EM energy into thermal energy or dissipate the EM waves through interference. [ 4,5 ] Among many kinds of microwave absorbers, carbon materials are always the most attractive candidates due to their tunable properties, relative low density, abundant resource, easy preparation, and low cost. Various carbon materials, e.g., carbon nanotubes (CNTs), carbon nanofi bers (CNF), carbon nanocoils, and mesoporous carbon, have been utilized to construct highly effective microwave absorbers in the past decades. [6][7][8][9][10][11][12] Although these carbon-based materials have made signifi cant progress in the fi eld of microwave absorption, some elaborate innovations on structure and components are still paving the way for exciting performance to satisfy the requirements of practical applications.Recently, graphene appeared as a fascinating material and grabbed worldwide attention, whose unprecedented physical and chemical properties derived from its unique 2D structure have promised great potential in many research fi elds. [ 13 ] Notably, high charge carrier mobility, extraordinary electrical and thermal conductivity also rendered graphene as a new microwave absorber, and it was found that reduced graphene oxide (rGO) provided superior microwave absorption to graphene oxide (GO). [ 14,15 ] However, sole graphene material suffers from limited loss mechanism caused by interfacial impedance mismatching, [ 15,16 ] thus it is usually employed as EM interference shielding material rather than EM absorbing material. [17][18][19] Incorporation of other lossy materials, especially magnetic metal and metal oxides, has been widely studied as the imperative solution to improve the matching of characteristic impedance and enhance the microwave absorption performance. [20][21][22][23][24][25][26][27][28][29] For example, graphene-coated Fe nanocomposites and Ni/graphene composites showed enhanced microwave absorption due to the charge transfer at metal/graphene interface and the polarization of free carriers; [ 20,21 ] Fe 3 O 4 /graphene, rGO-Fe 2 O 3 , and rGO/CNT-Fe 3 O 4 materials demonstrated optimum characteristic impedance and compatible dielectric and magnetic loss, which resulted in their strong refl ection loss in the frequency range of 12.0-16.0 GHz; [21][22][23] Graphene decorated with coreshell Fe@Fe 3 O 4 @ZnO nanoparticles was also fabricated, and Graphene-based composites offer immense potential for overcoming the challenges related to the performance, functionality, and durability in microwave absorption. In this study, a sandwich-like graphene-based composite is successfully fabricated by an interfacial engineering of amorphous carbon microspheres (ACMs) and reduced graphene oxide (rGO), with a structure of rGO/ACMs/rGO. The as-prepared rGO/ACMs/rGO composite presents comparable/superior refl ection loss characteristics in the frequency range of 2.0-18.0 GHz to previous composites of graphene and high-density magnetic particles. Electromagnetic parameters and simulation resu...

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mentioning

confidence: 99%

Interfacially Engineered Sandwich‐Like rGO/Carbon Microspheres/rGO Composite as an Efficient and Durable Microwave Absorber

Wang

Qiang

et al. 2016

Adv Materials Inter

135

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“…[23] This material is generally required to be bound to as olid matrix with low weighta nd high reflection loss. [24] Interfacial deposition of polyanilineo naPLA matrix was accomplished by loading aniline in an oil phase, which was subsequently exposed to FeCl 3 as an oxidanta fter complete removal of organic solvent. As shown in Figure 5a, al ayer of PANi was formed on the surface of porousP LA particles.…”

Section: à2mentioning

confidence: 99%

A Light‐Activated Microheater for the Remote Control of Enzymatic Catalysis

Cao

Wang

Liao

et al. 2015

Chemistry A European J

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The remote control of enzymatic catalysis is of significant importance in disease treatment and industrial applications. Herein, we designed a microheater composed of a porous polylactic acid (PLA) matrix and polydopamine (PDA) with notable photothermal conversion capability. Starch hydrolysis, catalyzed by using α-amylase, was accelerated in the presence of the microheater under illumination with near-infrared light or natural sunlight at room temperature. Additionally, the methodology was extended to the preparation of microwave-absorbing materials with the deposition of polyaniline on porous PLA matrix. The porous morphology improves the energy-conversion efficiency.

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“…[16][17][18][19][20] Although various yolkshell structures with different types of cores and different particle sizes have been successfully prepared, the control of shell thickness of yolk-shell type particles has been less well studies. [21][22][23] Therefore, the investigation of the control of thickness and crystalline structure of yolk-shell type particles is valuable. Here we report the control of shell thickness in yolk-shell particles.…”

Section: -15mentioning

confidence: 99%

Control of the Shell Thickness of TiO₂@SiO₂Particles and Its Surface Functionalization

Ahn¹,

Jung²,

Lee³

et al. 2013

Bulletin of the Korean Chemical Society

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The fabrication of functional hollow particles is of great scientific and technological interest for purposes of applications ranging from drug delivery, coatings, photonic devices, and nanoscale reaction vessels.1-3 Various methods, including approaches such as spray drying, emulsion templating techniques, and self-assembly processes, have been described for the preparation of hollow spheres out of latex, metal, and inorganic materials. 4-11Among the various structures of these particles, the coreshell structure is a powerful platform for controlled release, confined nanocatalysis and optical and electronic applications.12 A hybrid of the core-shell structure, termed the yolk-shell or rattle-type structure, is a special class of coreshell structures with a distinctive core@void@shell configuration which has attracted great interest in recent years. 13-15With the unique properties of movable cores, interstitial hollow spaces, and the functionalization of the shells, yolkshell structures have great potential for application in various fields, including nanoreactors, biomedicine, lithium-ion batteries, and photocatalysis. [16][17][18][19][20] Although various yolkshell structures with different types of cores and different particle sizes have been successfully prepared, the control of shell thickness of yolk-shell type particles has been less well studies.21-23 Therefore, the investigation of the control of thickness and crystalline structure of yolk-shell type particles is valuable. Here we report the control of shell thickness in yolk-shell particles. The crystalline structure of the yolkshell particle has also been characterized by annealing at different temperatures.The route for the preparation of yolk-shell (TiO 2 @SiO 2 ) titanium-silica particles is given in Scheme 1. After being dried in an oven at 50 °C for 2 h, titanium particles can be coated with silica under Stöber conditions. Silica coating of the dried titanium results in TiO 2 @SiO 2 particles. Upon calcination at 600-625 °C for 15-60 min, the greater porosity of the titanium cores of TiO 2 @SiO 2 particles causes them to shrink more than the silica component and gives rise to TiO 2 @SiO 2 particles.A TEM micrograph of the bare titanium particles is given in Figure 1(a) and the TiO 2 @SiO 2 particles, which display the shrinkage that occurred after calcination, are shown in Figure 1(b). We found the size of the particles to be 650-680 nm (5% polydispersity) and the shell thickness to be 100-120 nm, with an inner core of 340-360 nm. The void between the shrunken core and the silica shell was 70-130 nm depending on the particle size and the calcination time.To corroborate that the synthesized particles have SiO 2 layers, an elemental analysis was conducted to identify the presence of Si and SiO 2 in the particles.24 The EDX analysis showed that the TiO2@SiO2 core/shell particles consisted of Ti:Si in the ratio of 41:11% ( Figure S1). Furthermore, FTIR studies were also conducted to determine the presence of specific functional groups and intra and/o...

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Hierarchical Fe₃O₄@TiO₂ Yolk–Shell Microspheres with Enhanced Microwave‐Absorption Properties

Cited by 202 publications

References 47 publications

Interfacially Engineered Sandwich‐Like rGO/Carbon Microspheres/rGO Composite as an Efficient and Durable Microwave Absorber

Interfacially Engineered Sandwich‐Like rGO/Carbon Microspheres/rGO Composite as an Efficient and Durable Microwave Absorber

A Light‐Activated Microheater for the Remote Control of Enzymatic Catalysis

Control of the Shell Thickness of TiO₂@SiO₂Particles and Its Surface Functionalization

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Hierarchical Fe3O4@TiO2 Yolk–Shell Microspheres with Enhanced Microwave‐Absorption Properties

Cited by 202 publications

References 47 publications

Interfacially Engineered Sandwich‐Like rGO/Carbon Microspheres/rGO Composite as an Efficient and Durable Microwave Absorber

Interfacially Engineered Sandwich‐Like rGO/Carbon Microspheres/rGO Composite as an Efficient and Durable Microwave Absorber

A Light‐Activated Microheater for the Remote Control of Enzymatic Catalysis

Control of the Shell Thickness of TiO2@SiO2Particles and Its Surface Functionalization

Contact Info

Product

Resources

About

Hierarchical Fe₃O₄@TiO₂ Yolk–Shell Microspheres with Enhanced Microwave‐Absorption Properties

Control of the Shell Thickness of TiO₂@SiO₂Particles and Its Surface Functionalization