•Ni doped ZnO were synthesized by hydrothermal method.•High pulsed magnetic field was applied during the hydrothermal method.•The crystal sizes of samples decrease with pulsed magnetic field.•High pulsed magnetic field enhances the concentration of oxygen vacancies.•Oxygen vacancies are the key factor in Ni-doped ZnO DMS.Room temperature ferromagnetic 2% Ni doped ZnO rods were synthesized by high pulsed magnetic field-assisted hydrothermal method. A detailed study on the effect of high pulsed magnetic field on morphology, structural and magnetic properties of the ZnO rods has been carried out systematically by varying the intensity of field from 0 to 4 T. X-ray diffraction, Energy-dispersive spectroscopy measurements, and Raman spectra analysis suggest that all the samples have hexagonal wurtzite structure without detectable impurity. Field emission scanning electron microscopy images indicate that the particle size of samples decrease with increasing intensity of field. High resolution transmission electron microscopy observation ensures that the Ni ions addition do not change the wurtzite host matrix. X-ray photoelectron spectroscopy confirms the incorporation of Ni elements as divalent state and the dominant presence of oxygen vacancies in samples fabricated under 4 T pulsed magnetic field. Hysteresis loops demonstrate that the saturation magnetization increased regularly with the mounting magnetic field. On the framework of bound magnetic polaron model, the rising content of oxygen vacancies, as donor defect, lead to the stronger ferromagnetism in samples with pulsed magnetic field. Our findings provide a new insight for tuning the defect density by precisely controlling the intensity of field in order to get the desired magnetic behavior at room temperature.This figure shows the magnetization versus magnetic field curves for 2%Ni doped ZnO as prepared with 0, 1, 2, 3 and 4 T pulsed magnetic field at 290 K. For 0 T sample, no ferromagnetic response is observed. But all the samples synthesized with field were well-defined hysteresis loops. The saturation magnetization estimated from the hysteresis loop come out to be ∼0.0024, 0.0023, 0.0036 and 0.0061 emu/g for 1 T, 2 T, 3 T and 4 T samples, respectively. As shown in the curves, the room-temperature ferromagnetism improved with the increasing intensity of pulsed magnetic field.

•Core-shell structured ZnO@C is synthesized by the extended Stöber method.•The ZnO@C composite consists of a 160 nm ZnO core and a 20 nm carbon shell.•The ZnO@C electrode offers a high capacity and excellent rate capability.A core-shell structured design of ZnO@C nanosphere with uniform particle size of 200 nm has been successfully synthesized by a facile route - extended Stöber method. The well designed ZnO@C nanosphere shows a typical core-shell structure with a ~160 nm core and ~20 nm carbon shell which could improve their stability and performance as electrodes for lithium ion batteries (LIBs). When used as anode materials for LIBs, the core-shell structured ZnO@C nanospheres give a reversible capacity of 496 mA h g−1 after 200 cycles at a current density of 82.5 mA g−1. The amazing enhanced electrical performance can be contributed to the core-shell structured, which prevents the pulverization of anode during charge/discharge process.

Nano-sized composite with LiFePO4-core and carbon-shell was synthesized via a facile route followed by heat treatment at 650 °C. X-ray diffraction (XRD) shows that the core is well crystallized LiFePO4. The electron microscopy (SEM and TEM) observations show that the core-shell structured LiFePO4/C composite coating with whole carbon shell layer of ∼2.8 nm, possesses a specific surface area of 51 m2 g−1. As cathode material for lithium ion battery, the core-shell LiFePO4/C composite exhibits high initial capacity of 161 mAh g−1 at 0.1 C, excellent high-rate discharge capacity of 135 mAh g−1 at 5 C and perfect cycling retention of 99.6% at 100th cycle. All these promising results should be contributed to the core-shell nanostructure which prevents collapse of the particle structure in the long-term charge and discharge cycles, as well as the large surface area of the nano-sized LiFePO4/C composite which enhances the electronic conductivity and shortens the distance of lithium ion diffusion.Nano-sized LiFePO4/C composite with core-shell structure was fabricated via a well-designed approach as cathode material forlithium ion battery. The nano-sized LiFePO4/C composite with whole carbon shell coating layer showed an excellent electrical performance.

Sn/SnO2@C composite nanofibers were successfully fabricated by a facile annealing strategy. The composite consists of an amorphous carbon matrix encapsulating carbon nanotubes decorated by ultrafine (<10 nm) SnO2 nanoparticles, with submicron Sn particles incorporated in the entangled networks of the composite nanofibers. When used as anode material for lithium ion batteries, the Sn/SnO2@C composite nanofibers exhibited high initial charge capacity of 756 mAh g−1 at 100 mA g−1, excellent high-rate capacity of 190 mAh g−1 at 5 A g−1, and excellent capacity retention of 591 mAh g−1 after 100 cycles at 100 mA g−1. High-resolution transmission electron microscopy, energy dispersive spectroscopy mapping, X-ray photoelectron spectroscopy, and electrochemical impedance spectroscopy were applied to investigate the origins of the excellent electrochemical Li+ storage properties of Sn/SnO2@C. It could be deduced that the ductile carbon matrix and free spaces in the composite nanofiber networks can effectively accommodate the strain of volume change during cycling, prevent the aggregation and pulverization of Sn/SnO2 particles, keep the whole structure stable, and facilitate electron and ion transport through the electrode.

Pulse magnetic field-assisted hydrothermal method was used for the preparation of Cr–Ni codoped ZnO diluted magnetic semiconductors. XRD analysis reveals that all the samples have hexagonal wurtzite structure. HRTEM, EDS measurements and XPS results ensure that the divalent Cr and Ni ions have incorporated in the wurtzite host matrix without any detectable impurity phase formed. M–H and ZFC/FC curves of the samples reveal the enhancement of ferromagnetism resulted from the magnetic field processing. XPS measurement and Raman scattering spectra indicate that the content of oxygen vacancies in the sample increases with pulse magnetic field processing. According to the bound magnetic polaron model, this may be the reason for the sample with magnetic field processing having better ferromagnetism than that without field processing.

•Dense composite electrolyte hollow fibre membranes for high temperature carbon dioxide separation were developed.•The maximum carbon dioxide flux achieved was 1.0 mL cm−2 min−1 at 900 °C for the resultant composite hollow fibre membrane.•The membrane performed favorably in comparison with the published results.Inorganic membranes for high temperature CO2 separation has potential applications in clean energy delivery for CO2 capture. In this work, the gas tight oxygen ion conducting perovskite and carbonate composite electrolyte hollow fibre membranes were developed for CO2 separation at high temperatures. For this purpose, the La0.6Sr0.4Co0.2Fe0.8O3−α (LSCF) perovskite hollow fibre was firstly prepared as the porous support to impregnate and immobilize the carbonate phase. The composite electrolyte hollow fibre membranes were characterised by SEM, XRD, room-temperature gas leakage detection and CO2 permeation test at temperature regime from 500 to 900 °C. The maximum CO2 flux measured reached 1.0 mL cm−2 min−1 at 900 °C, which was improved by a factor up to 5 when compared with the previously developed membranes due to the much thinner separating layer achieved in the current membrane.

Mn-doped ZnO nanocrystal have been synthesized by the hydrothermal method under a 4 T pulsed magnetic field. X-ray diffraction (XRD) and scanning electron microscopy (SEM) characterizations reveal the samples are nano-columns with a hexagonal wurtzite ZnO structure. Raman measurement indicates that internal stress and structure defects of the samples increase due to the Mn atoms intercalate into the ZnO crystal lattice. Vibrating sample magnetometer (VSM) detection reveals well room-temperature ferromagnetism for our Mn-doping samples. The origin of room-temperature ferromagnetism may arise from the exchange interaction between Mn2+ ions and defects in ZnO. Combined with XRD, Raman and VSM measurement, it can also find that high pulsed magnetic field introduces more defects into Mn-doped ZnO samples, thus leads to the enhancement of their saturation magnetization.