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SrFe 12 O 19 is widely used due to its low cost, stability and corrosion resistance. In this study, Sm-doped porous SrFe 12 O 19 powder with high coercivity was synthesized using KCl- assisted spray pyrolysis. The Sm doping, microstructure and magnetic properties were studied by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM) and vibrating sample magnetometer (VSM). The results showed that when Sm-doping amount was 0.2, the ferrite powder prepared by KCl-assisted spray pyrolysis had high coercivity of 7.286 kOe and saturation magnetization of 56.422 emu/g. The coercivity of the Sm-doped samples increased by 39.23 % compared with that of the undoped samples. The significant increase in coercivity was associated with the improvement of super-exchange interaction between Fe3+ particles caused by Sm doping, and the size decrease of the hexagonal plate Sr-ferrite particle caused by KCl action. The influencing mechanism of coercivity was discussed in detail based on the analysis of crystal structure and microstructure observation. [ABSTRACT FROM AUTHOR]

Superhydrophobic SiO 2 was rapidly synthesized from commercial SiO 2 (KH550–SiO 2) at room temperature by innovatively using ultrasound-assisted ball milling. Characterization results showed that N-octyltriethoxysilane was grafted onto KH550–SiO 2 via multiple forces. Superhydrophobic paints were prepared by introducing epoxy resin as a binder. The preparation process is fluorine-free and green. Superhydrophobic paints can easily establish superhydrophobic coating on different substrates through multiple routes, and the prepared coating highlights excellent hydrophobicity, mechanical stability, and durability. Furthermore, the superhydrophobic coating displays superior self-cleaning, antifouling, oil-water separation, and load-increasing properties. We are sure that this work provides a novel green, fast, and scalable route for the synthesis of superhydrophobic nanoparticles. Also, it can promote the engineering applications of superhydrophobic coating. [ABSTRACT FROM AUTHOR]

Superhydrophobic SiO 2 was rapidly synthesized from commercial SiO 2 (KH550–SiO 2) at room temperature by innovatively using ultrasound-assisted ball milling. Characterization results showed that N-octyltriethoxysilane was grafted onto KH550–SiO 2 via multiple forces. Superhydrophobic paints were prepared by introducing epoxy resin as a binder. The preparation process is fluorine-free and green. Superhydrophobic paints can easily establish superhydrophobic coating on different substrates through multiple routes, and the prepared coating highlights excellent hydrophobicity, mechanical stability, and durability. Furthermore, the superhydrophobic coating displays superior self-cleaning, antifouling, oil-water separation, and load-increasing properties. We are sure that this work provides a novel green, fast, and scalable route for the synthesis of superhydrophobic nanoparticles. Also, it can promote the engineering applications of superhydrophobic coating. [ABSTRACT FROM AUTHOR]

Developing cathodes that are both phase-stable and tolerant to carbon dioxide (CO 2) is a crucial and challenging task for solid-oxide fuel cells (SOFCs) operating at reduced temperatures. The activity of oxygen reduction reaction (ORR) in SOFC cathodes is typically influenced by factors such as geometric features and oxygen vacancies. In this study, new and robust cathodes for SOFCs, Sr 2 Co 1.5 Fe 0.4 Ta 0.1 O 5+δ (SCFT) and Sr 2 Co 1.5 Fe 0.4 Nb 0.1 O 5+δ (SCFN) are developed by doping a small amount of niobium (Nb) and tantalum (Ta) into Sr 2 Co 1.6 Fe 0.4 O 5+δ (SCF) using a simple solid-state reaction technique. The effects of Nb/Ta doping on the crystal structure, oxygen vacancies, electrical conductivity, and electrochemical properties of SCFT and SCFN are investigated. The results reveal that these materials possess a fully cubic structure in the Fm-3m space group, with improved oxygen vacancy and electrical conductivity. They also exhibit good chemical compatibility with electrolytes at 1100 °C for 8 h and remain thermally stable when exposed to air and CO 2 at 700 °C, without any additional phase formation. The area-specific resistance (ASR) of the SCFT cathode is found to be only 0.06 Ω cm2, whereas the SCFN cathode has an ASR of 0.10 Ω cm2. The superior performance of SCFT can be attributed to the higher oxygen vacancy, which enhances oxygen surface exchange kinetics and diffusivity compared to SCFN. When tested in a single cell using humidified H 2 as the fuel and ambient air as the oxidant, the SCFT cathode achieves a power density of 656 mW cm−2 at 700 °C, while the SCFN cathode reaches 559 mW cm−2, indicating the potential of SCFT as a promising cathode material for SOFCs. The excellent performance of these materials can be attributed to their mixed electronic-ionic conduction properties, unique structural features, and high observed oxygen vacancy, which contribute to their remarkable electronic conductivity and significant ionic mobility. [ABSTRACT FROM AUTHOR]

The miniaturization of electronic components has become a megatrend in the future, making colossal dielectric permittivity materials receive unprecedented attention. In this work, we proposed a universal route to achieve colossal dielectric permittivity, low loss factor and excellent dielectric temperature stability in rare earth doped perovskite oxide SrTiO 3. Sm doped SrTiO 3 ceramics prepared by high-energy ball milling exhibit ultrahigh dielectric permittivity 441,543, low loss factor 0.02, good dielectric temperature stability (<15 %) in the temperature range of −55–200 °C, and very high resistance 109Ω, which meets the EIA X9R standard, XPS and impedance spectra indicate that the electron-pinned defect-dipoles effect is the origin of colossal dielectric permittivity and low loss factor. This work shows that Sm-doped SrTiO 3 activated by high-energy ball milling has broad prospects in the applications of thermally-stable miniaturized capacitors. [ABSTRACT FROM AUTHOR]