The sluggish kinetics of the oxygen evolution reaction(OER),an essential half-reaction of water splitting,lead to high OER overpotential and low energy-conversion efficiency,hampering its industrial application.Theref...The sluggish kinetics of the oxygen evolution reaction(OER),an essential half-reaction of water splitting,lead to high OER overpotential and low energy-conversion efficiency,hampering its industrial application.Therefore,considerable attention has been paid to the development of efficient catalysts to accelerate the OER.In this study,we synthesized the high-entropy oxides[(FeCoNiMnV)_(x)O]and used them as efficient OER catalysts.A simple oil-phase method was used to synthesize(FeCoNiMnV)_(x)O.The catalytic performances of the(FeCoNiMnV)_(x)O catalysts were modified by tuning the reaction temperature.The optimized(FeCoNiMnV)_(x)O catalyst exhibited multiple elemental interactions and abundant exposed active sites,leading to an overpotential of approximately 264 mV to reach a current density of 10 mA cm^(-2) in 1 M KOH and stability of 50 h at 1000 mA cm^(-2).Thus,a highly active OER catalyst was synthesized.This study provides an efficient approach for the synthesis of high-entropy oxides.展开更多
Perovskite-type Ba0.5Sr0.5Co0.8Fe0.2O3-σ （BSCFO） powders were synthesized using two methods, solid-state reaction （SSR） method and citrate-EDTA complexing method （CC-EDTA）. Then the powders were pressed to gree...Perovskite-type Ba0.5Sr0.5Co0.8Fe0.2O3-σ （BSCFO） powders were synthesized using two methods, solid-state reaction （SSR） method and citrate-EDTA complexing method （CC-EDTA）. Then the powders were pressed to green disks of 19 nun in diameter and sintered at 1140℃ for 5 h. The shrinkage rate and relative density of the membranes prepared from the perovskite-type powders were determined and calculated, and the powders and derived membranes were characterized by X-ray diffraction （XRD） and scanning electron microscopy （SEM）. The resuits show that the shrinkage rates of the two kinds of disks are nearly the same （about 10%）. The disks prepared by the SSR method had a bigger grain size and lower relative density than those prepared by the CC-EDTA method. The conductivity of the membranes prepared by the SSR method was about 38 S/cm, higher than that of the membranes prepared by the CC-EDTA method, which was about 30 S/cm, at the same temperature of600℃.展开更多
The Ca-Sn co-substituted yttrium iron garnet(YIG)ferrite materials were prepared by the traditional oxide solid-state reaction method,and the influence of forming pressure on the density,morphology and magnetic proper...The Ca-Sn co-substituted yttrium iron garnet(YIG)ferrite materials were prepared by the traditional oxide solid-state reaction method,and the influence of forming pressure on the density,morphology and magnetic properties of YIG ferrite was systematically studied.The results show that the density of YIG ferrite green body increases with the increase of the forming pressure,while the density of its sintered body shows a trend of first increasing and then decreasing.At the same time,the ferromagnetic resonance(FMR)linewidth of YIG sample first decreases and then increases.Meanwhile,the effects of forming pressure on the saturation magnetization,remanence and coercivity of the sample can be ignored.This study proves that the density and FMR linewidth of YIG materials can be controlled by regulating the forming pressure and the best performance is obtained for the sample prepared under a forming pressure of 5 MPa.展开更多
文摘The sluggish kinetics of the oxygen evolution reaction(OER),an essential half-reaction of water splitting,lead to high OER overpotential and low energy-conversion efficiency,hampering its industrial application.Therefore,considerable attention has been paid to the development of efficient catalysts to accelerate the OER.In this study,we synthesized the high-entropy oxides[(FeCoNiMnV)_(x)O]and used them as efficient OER catalysts.A simple oil-phase method was used to synthesize(FeCoNiMnV)_(x)O.The catalytic performances of the(FeCoNiMnV)_(x)O catalysts were modified by tuning the reaction temperature.The optimized(FeCoNiMnV)_(x)O catalyst exhibited multiple elemental interactions and abundant exposed active sites,leading to an overpotential of approximately 264 mV to reach a current density of 10 mA cm^(-2) in 1 M KOH and stability of 50 h at 1000 mA cm^(-2).Thus,a highly active OER catalyst was synthesized.This study provides an efficient approach for the synthesis of high-entropy oxides.
基金supported by the National High-Tech Research and Development Program of China (No. 2006AA11A189) the National Natural Science Foundation of China (No. 50730004)
文摘Perovskite-type Ba0.5Sr0.5Co0.8Fe0.2O3-σ （BSCFO） powders were synthesized using two methods, solid-state reaction （SSR） method and citrate-EDTA complexing method （CC-EDTA）. Then the powders were pressed to green disks of 19 nun in diameter and sintered at 1140℃ for 5 h. The shrinkage rate and relative density of the membranes prepared from the perovskite-type powders were determined and calculated, and the powders and derived membranes were characterized by X-ray diffraction （XRD） and scanning electron microscopy （SEM）. The resuits show that the shrinkage rates of the two kinds of disks are nearly the same （about 10%）. The disks prepared by the SSR method had a bigger grain size and lower relative density than those prepared by the CC-EDTA method. The conductivity of the membranes prepared by the SSR method was about 38 S/cm, higher than that of the membranes prepared by the CC-EDTA method, which was about 30 S/cm, at the same temperature of600℃.
文摘The Ca-Sn co-substituted yttrium iron garnet(YIG)ferrite materials were prepared by the traditional oxide solid-state reaction method,and the influence of forming pressure on the density,morphology and magnetic properties of YIG ferrite was systematically studied.The results show that the density of YIG ferrite green body increases with the increase of the forming pressure,while the density of its sintered body shows a trend of first increasing and then decreasing.At the same time,the ferromagnetic resonance(FMR)linewidth of YIG sample first decreases and then increases.Meanwhile,the effects of forming pressure on the saturation magnetization,remanence and coercivity of the sample can be ignored.This study proves that the density and FMR linewidth of YIG materials can be controlled by regulating the forming pressure and the best performance is obtained for the sample prepared under a forming pressure of 5 MPa.
