In modern metallurgical industry,microwave thermal technique has many advantages as one efficient energy treatment in an electromagnetic form,such as internal self-generated heat,easy access to control a volumetric he...In modern metallurgical industry,microwave thermal technique has many advantages as one efficient energy treatment in an electromagnetic form,such as internal self-generated heat,easy access to control a volumetric heating process,and consensus on cleanliness,convenience and high efficiency of energy use.Both permittivity and permeability of molybdenite concentrate were measured for a further discussion about its electromagnetic heating coupling.A bidirectional coupling physics field in numerical modeling was undertaken to evaluate the microwave absorption potential and dielectric heating performance of molybdenite concentrate by the multi-physics finite element method.The electromagnetic morphology and the field distribution strength were described in the microwave reaction cavity.The electromagnetic field strength and the dissipation coefficient induced by temperature variation were represented throughout the whole heat chamber and at key parts of interest.Dependent temperature distribution was compared with that being obtained from a scenario by thermal conduction with a stable heat source.The molybdenite concentrate would be heated at surrounding temperature up to 593℃for 10 min by microwave energy that was transmitted by a rectangular waveguide.Scanning electron microscopy(SEM)patterns suggested that the polished and neat crystalline molybdenum trioxide(MoO_(3))products were achieved by the microwave heating process.The superiority via utilizing microwave thermal technique is expounded in the preparation strategy for molybdenum oxide or molybdenum metal.展开更多
Photo-assisted lithium-oxygen(Li-O_(2))batteries have been developed as a new system to reduce a large overpotential in the Li-O_(2)batteries.However,constructing an optimized photocatalyst is still a challenge to ach...Photo-assisted lithium-oxygen(Li-O_(2))batteries have been developed as a new system to reduce a large overpotential in the Li-O_(2)batteries.However,constructing an optimized photocatalyst is still a challenge to achieve broad light absorption and a low recombined rate of photoexcited electrons and holes.Herein,oxygen vacancy-rich molybdenum trioxide(MoO_(3-x))nanorods are employed as photocatalysts to accelerate kinetics of cathode reactions in the photo-assisted Li-O_(2)batteries.Oxygen vacancies on the MoO_(3-x)nanorods can not only increase light-harvesting capability but also improve electrochemical activity for the cathode reactions.Under illumination,the photoexcited electrons and holes are effectively separated on the MoO_(3-x)nanorods.During discharging,activated O2 is reduced to Li_(2)O_(2)by the photoexcited electrons from the MoO_(3-x)nanorods.The photoexcited holes can promote the decomposition of Li_(2)O_(2)during subsequent charging.Accordingly,the photo-assisted Li-O_(2)batteries with the MoO_(3-x)nanorods deliver an ultralow overpotential of 0.22 V,considerable rate capability,and good reversibility.We think that this work could give a reference for the exploitation and application of the photocatalysts in the photo-assisted Li-O_(2)batteries.展开更多
基金Educational Science and Technology Project,Educational Department of Guizhou Province,China(No.2022005)。
文摘In modern metallurgical industry,microwave thermal technique has many advantages as one efficient energy treatment in an electromagnetic form,such as internal self-generated heat,easy access to control a volumetric heating process,and consensus on cleanliness,convenience and high efficiency of energy use.Both permittivity and permeability of molybdenite concentrate were measured for a further discussion about its electromagnetic heating coupling.A bidirectional coupling physics field in numerical modeling was undertaken to evaluate the microwave absorption potential and dielectric heating performance of molybdenite concentrate by the multi-physics finite element method.The electromagnetic morphology and the field distribution strength were described in the microwave reaction cavity.The electromagnetic field strength and the dissipation coefficient induced by temperature variation were represented throughout the whole heat chamber and at key parts of interest.Dependent temperature distribution was compared with that being obtained from a scenario by thermal conduction with a stable heat source.The molybdenite concentrate would be heated at surrounding temperature up to 593℃for 10 min by microwave energy that was transmitted by a rectangular waveguide.Scanning electron microscopy(SEM)patterns suggested that the polished and neat crystalline molybdenum trioxide(MoO_(3))products were achieved by the microwave heating process.The superiority via utilizing microwave thermal technique is expounded in the preparation strategy for molybdenum oxide or molybdenum metal.
基金supported by the Jilin Province Science and Technology Department Program(Nos.YDZJ202101ZYTS047,YDZJ202201ZYTS304,20220201130GX,and 20200201187JC)the National Natural Science Foundation of China(Nos.52171210 and 21978110)the Science and Technology Project of Jilin Provincial EducationDepartment(Nos.JJJKH20210444KJ and JKH20220428KJ).
文摘Photo-assisted lithium-oxygen(Li-O_(2))batteries have been developed as a new system to reduce a large overpotential in the Li-O_(2)batteries.However,constructing an optimized photocatalyst is still a challenge to achieve broad light absorption and a low recombined rate of photoexcited electrons and holes.Herein,oxygen vacancy-rich molybdenum trioxide(MoO_(3-x))nanorods are employed as photocatalysts to accelerate kinetics of cathode reactions in the photo-assisted Li-O_(2)batteries.Oxygen vacancies on the MoO_(3-x)nanorods can not only increase light-harvesting capability but also improve electrochemical activity for the cathode reactions.Under illumination,the photoexcited electrons and holes are effectively separated on the MoO_(3-x)nanorods.During discharging,activated O2 is reduced to Li_(2)O_(2)by the photoexcited electrons from the MoO_(3-x)nanorods.The photoexcited holes can promote the decomposition of Li_(2)O_(2)during subsequent charging.Accordingly,the photo-assisted Li-O_(2)batteries with the MoO_(3-x)nanorods deliver an ultralow overpotential of 0.22 V,considerable rate capability,and good reversibility.We think that this work could give a reference for the exploitation and application of the photocatalysts in the photo-assisted Li-O_(2)batteries.
