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Ba 1-x Sm 1-x SnO 3 (BSSO, x = 0.00, 0.02, 0.04, 0.06, 0.08, 0.10 and 0.15) thin films were epitaxially grown on (001) oriented MgO substrates by pulsed laser deposition (PLD) technique. The structure analysis was performed by x-ray diffraction (XRD), including 2theta-omega (2θ-ω) scans, omega (ω) scans, phi (φ) scans, and reciprocal space mapping (RSM). Hall effect measurement shows that the lowest room temperature resistivity value can reach to 7.842 mΩ cm in the 0.04 Sm-doped thin film, while the carrier mobility ( μ ) decreases systematically with increasing Sm doping content. Temperature dependent resistivity behavior indicates that the BSSO films exhibit metal-semiconductor transition in the temperature range of 10–300 K with the doping content up to x = 0.08. Optical transmission spectra measurement shows that all the BSSO films exhibit a high transmittance of more than 80% in the visible range. The increasing of optical band gap E g with the increase of Sm doping content was interpreted by the Burstein-Moss effect and the occurrence of octahedral tilt distorting. Excellent optical and electrical properties mean that the BSSO films have potential applications as transparent and conducting oxide (TCO) material. [ABSTRACT FROM AUTHOR]

Monodispersed and uniform hexagonal thin plate-like magnesium-aluminum layered double hydroxide intercalated with CO 3 2− (MgAl–CO 3 2− -LDH) is synthesized by an ethanol–water mediated solvothermal method. The maximum adsorption capacities of the as-synthesized and calcined MgAl − CO 3 2 − − LDH are 129.9 and 143.27 mg g −1 , respectively, which are higher than those of the other metal oxide nanostructures reported to date. More importantly, although N 2 adsorption–desorption analysis indicates that the BET surface area changed from 24.74 m 2 g −1 for the as-synthesized MgAl − CO 3 2 − − LDH to 165.07 m 2 g −1 for the calcined MgAl − CO 3 2 − − LDH , the as-synthesized and calcined hexagonal thin plate-like MgAl − CO 3 2 − − LDH structures show similar adsorption capacity of Congo red (CR) from aqueous solution. The adsorption mechanism for the as-prepared LDH is anion exchange while adsorption mechanism for the calcined LDH is reconstruction. Our study opens a new insight for understanding and preparing high-performance adsorbents for organic dye removal. [ABSTRACT FROM AUTHOR]

Many nanomaterials have been widely reported for removal of toxic inorganic metal ions. However, some nanoscale adsorbents are subject to serious aggregation. For example, it is very difficult to directly synthesize the monodispersed Fe(OH) 3 nanomaterials. Here, through using the monodispersed hierarchical γ-Al 2 O 3 nanoflowers as adsorbent supports, the Fe(OH) 3 colloid nanoparticles have been well deposited onto the surfaces of the hierarchical γ-Al 2 O 3 nanostructures to form γ-Al 2 O 3 /Fe(OH) 3 composites with hierarchical structures via an electrostatic attraction without forming large aggregates. The γ-Al 2 O 3 /Fe(OH) 3 composites with hierarchical structures have high specific surface areas and large pore volumes, which are used as adsorbents to remove anion species of As(V) and Cr(VI) from aqueous solution. The maximum capacities of the monodispersed γ-Al 2 O 3 /Fe(OH) 3 composites with hierarchical structures for As(V) and Cr(VI) are determined at 61.99 mg g −1 and 24.13 mg g −1 , respectively, which are higher than those of the other metal oxide nanostructures reported. In addition, the adsorption rates of As(V) and Cr(VI) onto the monodispersed γ-Al 2 O 3 /Fe(OH) 3 composites with hierarchical structures are rather fast. The γ-Al 2 O 3 /Fe(OH) 3 hierarchical micro/nanoflower structures show high adsorption capacity for removing anion species of As(V) and Cr(VI), demonstrating a promising potential in environmental remediation. [ABSTRACT FROM AUTHOR]

Fe-ethylene glycol (Fe-EG) complex was synthesized using a facile and surfactant-free solvothermal method, and was characterized by field emission scanning electron microscopy (SEM), bright field transmission electron microscopy(TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), thermal gravimetric analysis (TGA) and X-ray photoelectron spectroscopy (XPS). The obtained Fe-EG complex was an excellent candidate for synthesis of various iron oxides micro/nanostructures by a simple calcination approach. In an air atmosphere, γ-Fe 2 O 3 , γ-Fe 2 O 3 /α-Fe 2 O 3 nanocomposites, and α-Fe 2 O 3 micro/nanostructures were successfully prepared by controlling the calcination temperature. Fe 3 O 4 micro/nanostructures were also synthesized by calcination the Fe-EG complex under an argon atmosphere. The magnetic properties of the obtained series of iron oxides micro/nanostructures were studied, and the saturation magnetisation of the obtained γ-Fe 2 O 3 and Fe 3 O 4 were 65.91 and 100.20 emu g −1 , respectively. The results of the work put forward a simple and effective approach for the synthesis of iron oxides micro/nanostructures with controlled chemical composition and good magnetic properties. [ABSTRACT FROM AUTHOR]

Ba(Nb x Sn 1- x )O 3 (BNSO) films were epitaxially grown on (001) oriented MgO substrates with Nb doping content from 0.00 to 0.15 by pulsed laser deposition. The structural, electrical, and optical properties of the films were investigated in detail by x-ray diffraction, x-ray photoelectron spectroscopy, Hall effect and transmittance spectroscopy. The lowest room temperature resistivity value of 4.81 × 10 −4 Ω cm with carrier concentration and mobility of 6.59 × 10 20 /cm 3 and 19.65 cm 2 /V was observed in the film at x = 0.05, indicating an excellent electrical conductivity. All the BNSO films exhibit a high transmittance of more than 80% in the visible range. The variation of band gap E g with Nb doping content was interpreted by the Burstein-Moss effect and the occurrence of octahedral tilt distorting. Excellent optical and electrical properties suggest that BNSO films have potential applications in the optoelectronic devices as transparent and conducting oxide material. [ABSTRACT FROM AUTHOR]

Over a long period of time, single iron oxide (Fe 2 O 3 ) or cobalt oxide (Co 2 O 3 ) has been extensively studied for magnetic absorbing materials. Recently, some nanoscale compounds composed of two ferrites have been reported for better electromagnetic absorbing properties because of collectively corporation. However, there are few reports about other magnetic absorbing materials. In addition, morphology control for better absorbing performance remains challenging. Here, the monodispersed, uniform rod-shaped FeCO 3 /CoCO 3 microparticles are successfully synthesized by a facile one-step solvothermal method for the first time. The experimental results show that the reflection loss (RL) value of the paraffin composites with thickness of 2.0 mm is less than −10 dB in the frequency range of 6.72–15.92 GHz and the minimum RL value of −31.86 dB at 12.88 GHz is obtained, which demonstrates that the as-prepared FeCO 3 /CoCO 3 microparticles have excellent magnetic and microwave absorbing properties. [ABSTRACT FROM AUTHOR]

This article employs a hydrothermal method combined with a calcination process to prepare Co 3 O 4 microsheets with varying Ni doping concentrations. Microstructural analysis reveals that the obtained samples are single-phase, free from other impurities, and exhibit a unique self-assembled porous micro-nanostructure. The micron-sized secondary aggregates consist of small nanometer-sized particles with many voids. The nanoscale pores between the nanoparticles contribute to the dissipation of incident microwaves. The dielectric and magnetic properties of Co 3 O 4 microplates can be effectively tuned by adjusting the Ni doping concentration. Comparative results indicate that the Ni-doped Co 3 O 4 microsheets with 0.03 mol% Ni exhibit the minimum reflection loss (RL min) of −34.7 dB at 16.56 GHz, with a thickness of just 1.4 mm. Simultaneously, the effective absorption bandwidth (EAB) reaches 4.32 GHz within the frequency range of 13.68–18 GHz. With an absorber thickness of 1.5 mm, the EAB can reach 5.2 GHz from 12.8 to 18 GHz. By adjusting the matching thickness of the absorber in the range of 1.4–4.5 mm, the EAB of Ni-doped Co 3 O 4 can cover multiple frequency bands from 3.6 to 18 GHz. The outstanding microwave absorption performance primarily stems from the unique porous micro-nanostructure and enhanced dielectric and magnetic losses. The results provide an effective component regulating strategy to promote microwave absorption, meanwhile suggest that the low-cost Ni-doped Co 3 O 4 is a promising microwave absorption material. • Micro-nano porous structure Ni-doped Co 3 O 4 has been constructed. • The absorption properties are improved effectively by Ni doping. • Minimum reflection loss of −34.7 dB is obtained at just 1.4 mm. • Effective absorption bandwidth (RL<-10 dB) is up to 5.2 GHz at 1.5 mm. [ABSTRACT FROM AUTHOR]

In this paper, low Ni-doped Co 3 O 4 (Ni: 2 wt%, 4 wt%, 6 wt% and 8 wt%) porous nanoplates are synthesized by hydrothermal method and annealing treatment. For the low Ni-doped Co 3 O 4 , X-ray diffraction (XRD) and Raman data show that the Ni ions are successfully incorporated into the Co 3 O 4 lattices. Electrochemical measurements indicate that Co 3 O 4 with low amount of Ni doping possesses remarkably enhanced activity for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) in alkaline media. And especially, 4 wt% Ni-doped Co 3 O 4 possesses the most efficient activity with an overpotential of 240 mV at the current density of 10 mA cm−2 for OER and 120 mV for HER in 1 M KOH than the pure Co 3 O 4 and other Ni-doped Co 3 O 4 samples. Our study suggests that the low doping would have a great potential in rational design of spinel oxides toward highly efficient electrocatalysis. • The Ni-doped Co 3 O 4 porous nanoplates are successfully synthesized by hydrothermal method and annealing treatment. • This is the first report of low-doped Ni-doped Co 3 O 4 porous nanoplates for both OER and HER in alkaline media. • The 4 wt % Ni-doped Co 3 O 4 possesses the most efficient activity than the pure Co 3 O 4 and other Ni-doped Co 3 O 4 samples. [ABSTRACT FROM AUTHOR]

High-performance microwave absorption materials with tunable electromagnetic properties have long been the goal of researchers. It is still a challenge to achieve broad band absorption and lightweight performance by simply optimizing the chemical composition of absorbers. Molybdenum disulfide (MoS 2) belongs to the two-dimensional transition metal disulfide with a layered structure similar to graphene. In this work, two-dimensional MoS 2 /reduced graphene oxide (MS/RGO) hybrids have been constructed through a convenient self-assembled hydrothermal method, in which MoS 2 ultrathin nanosheets in-situ grow uniformly on the surface of RGO, constructing a unique hierarchical microstructure. Electromagnetic parameter measurements display that the dielectric behaviors of MS/RGO composites are optimized via changing the content of RGO, and meanwhile the superior microwave absorption properties are achieved with the filler-loading ratio of only 20 wt%. The widest effective absorption bandwidths (RL<−10 dB) of 5.68 GHz (12.32–18 GHz) and 6.32 GHz (11.20–17.52 GHz) are observed at a thickness of 2.0 mm for MS/RGO-10 and MS/RGO-15, respectively. When the thickness is raised to 5.0 mm, the reflection loss value of MS/RGO-10 composites reaches the minimum value of − 39.8 dB at 4.96 GHz. The improved performance can be explained by the strong interfacial polarization loss due to abundant heterogeneous interfaces, defect dipole polarization, conduction loss, and multiple reflections and scattering. The results indicate that the light-weight MS/RGO composite is considered as a promising candidate for high-performance microwave absorbers with an adequate absorption bandwidth. • MoS 2 decorated RGO nanosheets have been constructed. • The absorption properties are improved effectively by the addition of RGO. • The sample with 20 wt% powders exhibit excellent absorption performance. • Effective absorption bandwidth (RL<−10 dB) is 6.32 GHz within 2 mm. • Minimum reflection loss of − 39.8 dB is obtained at 4.96 GHz. [ABSTRACT FROM AUTHOR]

Transparent and conductive Ta doped BaSnO 3 (BaSn 1−x Ta x O 3 , BSTO) films with x = 0–0.15 were epitaxially grown on MgO single crystalline substrates by a pulsed laser deposition method. The effects of Ta ions incorporation on the microstructure, electrical and optical properties of BSTO films were investigated. X-ray diffraction measurements indicate that the out-of-plane lattice parameters increase gradually with Ta concentration increasing, and the films are relaxed due to the large lattice mismatch between the films and substrate. Atomic force microscopy images reveal that all the films have smooth surface and low roughness. X-ray photoelectron spectra of BSTO films confirm that the Ta ions are presented in the +5 state. The lowest room-temperature resistivity and the highest carrier concentration and Hall mobility were observed in BSTO film at x = 0.07, with the values of 2.525 mΩcm, 5.024 × 10 20 cm −3 , and 4.921 cm 2 /Vs, respectively. Temperature dependent resistivity behavior shows that the BSTO films with low doping content exhibit metal-semiconductor transition at low temperature. The optical transmittances of all BSTO films are more than 80% in the visible region. The optical band gaps were found to increase from 3.52 to 4.23 eV with the increase of Ta doping content and can be attributed to the Burstein-Moss effect. Thus, the superior electrical and optical properties of Ta doped BaSnO 3 films are comparable to that of La and Sb doped BaSnO 3 films, and have potential applications in the optoelectronic devices. [ABSTRACT FROM AUTHOR]

In this work, a rare system of Sr 3 Co 2 Fe 24 O 41 /MoS 2 composites has been successfully prepared via the sol-gel method and following a facile hydrothermal process, from which the flower-like MoS 2 was evenly anchored on the surface of Z-type Sr 3 Co 2 Fe 24 O 41 microplatelets. It is confirmed that the effective combination of transition metal sulfide MoS 2 and multiferroic Sr 3 Co 2 Fe 24 O 41 hexaferrite greatly optimizes the dielectric behaviors of the composites. Meanwhile, the unique hierarchical structure further enhances the microwave absorption properties. When the mass ratio of Sr 3 Co 2 Fe 24 O 41 to MoS 2 is 1:3 in composites, the smallest reflection loss value is − 39.2 dB at the thickness of 2.0 mm, and note that the adequate absorption bandwidth can reach up to 7.6 GHz (10–17.6 GHz) with 2.2 mm. When the mass ratio is adjusted as 1:5, the optimal reflection loss of the composite reaches − 44.5 dB at 9.28 GHz with a thickness of 3.0 mm. The high-efficiency microwave absorption performance of the composites is attributed to the synergistic effect of dielectric materials and multiferroic materials. The calculation results on delta and attenuation constant display that impedance matching degree and attenuation ability of composites are balanced, which not only reduces the reflection of electromagnetic waves on the absorber surface, but also enhances its consumption. At the same time, the flower-shaped MoS 2 is stacked on the surface of Sr 3 Co 2 Fe 24 O 41 microplatelets which is conductive to the multiple reflections and scattering of electromagnetic waves between layers, greatly promoting the attenuation of electromagnetic waves. This work opens up an updated pathway for the design of magnetic/dielectric microwave absorbers with vigorous absorption and ultra-wideband. • Sr 3 Co 2 Fe 24 O 41 decorated MoS 2 nanosheets have been constructed. • The absorption properties are improved effectively by the addition of MoS 2. • Effective absorption bandwidth (RL<−10 dB) is 7.6 GHz within 2.2 mm. • Minimum reflection loss of − 44.5 dB is obtained at 9.28 GHz. [ABSTRACT FROM AUTHOR]

(Ba 1-x Gd x )SnO 3 (BGSO) (x = 0–0.15) films were epitaxially grown on MgO substrates by pulsed laser deposition. Structure analysis was performed using X-ray diffraction, atomic force microscopy, and X-ray photoelectron spectroscopy. Transport properties were investigated by Hall effect and temperature dependent resistivity measurement. Results show that the film resistivity decreases systematically with increasing Gd doping concentration. The lowest room-temperature resistivity of 6.18 mΩcm was observed in film at x = 0.07, with the metal-insulator transition at 30 K, which was attributed to the formation of a degenerate band in films. Optical transmission spectra measurement shows that all the BGSO films have high transmittance of more than 80% in the visible range. The band gap variation with the Gd doping concentration was interpreted by the Burstein-Moss effect. Excellent optical and electrical properties suggest that BGSO films have potential applications in the optoelectronic devices as transparent and conducting oxide material. [ABSTRACT FROM AUTHOR]

In this article, the CoFe 2 O 4 /MoS 2 composites have been well constructed via a facial hydrothermal method, from which the porous CoFe 2 O 4 microspheres were embedded into MoS 2 ultrathin nanosheets. As a typical two-dimensional transition metal sulfide, MoS 2 with high electrical conductivity and flexible properties is expected to exhibit high dielectric loss and magnetic loss when combined with magnetic material CoFe 2 O 4. Meanwhile, the unique hierarchical structure of as-synthesized MoS 2 nanoflowers is conducive to scattering and reflection of electromagnetic waves, and endows designed composites with competitive microwave absorption properties. Notably, although the saturation magnetization of MoS 2 /CoFe 2 O 4 composites is significantly decreased compared to pure CoFe 2 O 4 microspheres, the coercivity still maintains a high value of 626.1 Oe. As expected, the results demonstrate that as-fabricated MoS 2 /CoFe 2 O 4 composites do have superior microwave absorption properties in comparison with CoFe 2 O 4 and MoS 2. It is found that the complex permittivity is enhanced with increasing filling ratio from 45 wt% to 60 wt%, which is helpful for obtaining a moderate permittivity value. When the filling ratio is 50 wt%, the MoS 2 /CoFe 2 O 4 composites exhibit a minimum reflection loss (RL min) of − 53.1 dB at 12.08 GHz when the thickness is 2.5 mm. An effective absorption bandwidth less than − 10 dB of 6.61 GHz from 11.28 to 17.89 GHz is achieved with a thin thickness of 2.2 mm, almost covering the whole Ku-band. The improvement in microwave absorption properties can be ascribed to the synergistic effect of the magnetic CoFe 2 O 4 and dielectric MoS 2. The impedance matching characteristic and interfacial polarization are significantly optimized by inserting CoFe 2 O 4 spheres onto the surface of MoS 2 nanosheets. Considering the excellent performance of as-fabricated MoS 2 /CoFe 2 O 4 composites, it is believed that the MoS 2 -based composites can be applied as a promising candidate of highly effective microwave absorbers with strong absorption intensity and broad absorption frequency. • CoFe 2 O 4 spheres embedded into MoS 2 ultra-thin nanosheets have been constructed. • The optimal filling ratio of the composites is 50 wt%. • Minimum reflection loss of − 53.1 dB is obtained at 12.08 GHz. • Effective absorption bandwidth (RL<−10 dB) is 6.61 GHz within 2.2 mm. [ABSTRACT FROM AUTHOR]