The low separation efficiency of the photogenerated carrier and the poor activity of the surface redox reaction are the main barrier to further improvement of photocatalytic materials.To address these issues,introduci...The low separation efficiency of the photogenerated carrier and the poor activity of the surface redox reaction are the main barrier to further improvement of photocatalytic materials.To address these issues,introducing spin-polarized electrons in single-component photocatalytic materials emerged as a promising approach.However,the decreased redox ability of photocarriers in these materials becomes a new challenge.Herein,we mitigate this challenge with a carbon nitride sheet(CNs)/graphene nanoribbon(GNR)composite material that has a van der Waals heterostructures(vdWHs)and spin-polarized electron properties.Experimental results and theoretical calculations show that the heterostructure has a strong redox ability,high carrier-separation efficiency,and enhanced surface catalytic reaction.Consequently,the mixed-dimensional CNs/GNR vdWHs exhibit remarkable performance for H_(2)and O_(2)generation as well as CO_(2)production under visible-light irradiation without any cocatalyst.The spin-polarized vdWHs discovered in this study revealed a new type of photocatalytic materials and advanced the development of spintronics and photocatalysis.展开更多
A symmetrical Fe2O3/BaCO3 hexagonal cone structure having a height of 10 um and an edge length of -4um is reported, obtained using a common solvothermal process and a mirror growth process. Focused ion beam and high-r...A symmetrical Fe2O3/BaCO3 hexagonal cone structure having a height of 10 um and an edge length of -4um is reported, obtained using a common solvothermal process and a mirror growth process. Focused ion beam and high-resolution transmission electron microscopy techniques revealed that α-Fe2O3 was the single crystal feature present. Ba ions contributed to the formation of symmetrical structures exhibited in the final composites. Subsequently, porous magnetic symmetric hexagonal cone structures were used to study the observed intense electromagnetic wave interference. Electromagnetic absorption performance studies at 2-18 GHz indicated stronger attenuation electromagnetic wave ability as compared to other shapes such as spindles, spheres, cubes, and rods. The maximum absorption frequency bandwidth was at 7.2 GHz with a coating thickness d = 1.5 mm. Special structures and the absence of BaCO3 likely played a vital role in the excellent electromagnetic absorption properties described in this research.展开更多
In Ni-Mn-X（X=In,Sn,Sb） ferromagnetic shape memory alloys,a ferromagnetic transition from paramagnetic to ferromagnetic austenite and a martensitic transformation from ferromagnetic austenite to weak magnetic martens...In Ni-Mn-X（X=In,Sn,Sb） ferromagnetic shape memory alloys,a ferromagnetic transition from paramagnetic to ferromagnetic austenite and a martensitic transformation from ferromagnetic austenite to weak magnetic martensite occur in some particular composition ranges,in which abundant physical properties have been observed by the abrupt change of magnetization and resistivity around their transition temperatures in these alloys.Therefore,tuning the martensitic transformation temperature（TM） and enlarging the workingtemperature interval for Ni-Mn-X（X=In,Sn,Sb） alloys,are of great importance.In the present paper,we will focus on the effect of external factors,including pre-deformation,annealing,and high pressure annealing,on the magnetic transitions and the related magnetocaloric properties in Ni-Mn-Co-Sn ferromagnetic shape memory alloys.Our approaches and the main results in this particular field will be reviewed.展开更多
1.Introduction Refrigeration plays an essential role in nowadays society.However,conventional refrigeration based on vapor compression cooling shows high energy consumption,complicated structure and even environmental...1.Introduction Refrigeration plays an essential role in nowadays society.However,conventional refrigeration based on vapor compression cooling shows high energy consumption,complicated structure and even environmental pollution.Searching for an environmentalfriendly and energy-saving refrigeration technology has become a matter of concern[1,2].In the past few decades,the solid-state refrigeration technologies mainly represented by magnetocaloric effect(MCE),electrocaloric effect(ECE)and elastocaloric effect(e CE)have been regarded as promising candidate to replace traditional vapor compression refrigeration technology owing to environmental friendliness and high efficiency[1-9].展开更多
基金supported by the National Natural Science Foundation of China(Grant No.12104352 and 51973170)Fundamental Research Funds for the Central Universities(Grant No.XJS212208 and 2020BJ-56)+1 种基金Foundation of State Key Laboratory of High-efficiency Utilization of Coal and Green Chemical Engineering(Grant No.2022-K67)the National Natural Science Foundation of Shaanxi Province under Grant No.2019JCW-17 and 2020JCW-15.
文摘The low separation efficiency of the photogenerated carrier and the poor activity of the surface redox reaction are the main barrier to further improvement of photocatalytic materials.To address these issues,introducing spin-polarized electrons in single-component photocatalytic materials emerged as a promising approach.However,the decreased redox ability of photocarriers in these materials becomes a new challenge.Herein,we mitigate this challenge with a carbon nitride sheet(CNs)/graphene nanoribbon(GNR)composite material that has a van der Waals heterostructures(vdWHs)and spin-polarized electron properties.Experimental results and theoretical calculations show that the heterostructure has a strong redox ability,high carrier-separation efficiency,and enhanced surface catalytic reaction.Consequently,the mixed-dimensional CNs/GNR vdWHs exhibit remarkable performance for H_(2)and O_(2)generation as well as CO_(2)production under visible-light irradiation without any cocatalyst.The spin-polarized vdWHs discovered in this study revealed a new type of photocatalytic materials and advanced the development of spintronics and photocatalysis.
文摘A symmetrical Fe2O3/BaCO3 hexagonal cone structure having a height of 10 um and an edge length of -4um is reported, obtained using a common solvothermal process and a mirror growth process. Focused ion beam and high-resolution transmission electron microscopy techniques revealed that α-Fe2O3 was the single crystal feature present. Ba ions contributed to the formation of symmetrical structures exhibited in the final composites. Subsequently, porous magnetic symmetric hexagonal cone structures were used to study the observed intense electromagnetic wave interference. Electromagnetic absorption performance studies at 2-18 GHz indicated stronger attenuation electromagnetic wave ability as compared to other shapes such as spindles, spheres, cubes, and rods. The maximum absorption frequency bandwidth was at 7.2 GHz with a coating thickness d = 1.5 mm. Special structures and the absence of BaCO3 likely played a vital role in the excellent electromagnetic absorption properties described in this research.
基金supported by the National Basic Research Program of China (No. 2005CB623605)the National Natural Science Foundation of China (Nos. 50701022and 50831006)+1 种基金Jiangxi Provincial Sci&Tech Project(No. 2010AZX00200)the Program for New Century Excellent Talents of China (No. NCET-08-0278)
文摘In Ni-Mn-X（X=In,Sn,Sb） ferromagnetic shape memory alloys,a ferromagnetic transition from paramagnetic to ferromagnetic austenite and a martensitic transformation from ferromagnetic austenite to weak magnetic martensite occur in some particular composition ranges,in which abundant physical properties have been observed by the abrupt change of magnetization and resistivity around their transition temperatures in these alloys.Therefore,tuning the martensitic transformation temperature（TM） and enlarging the workingtemperature interval for Ni-Mn-X（X=In,Sn,Sb） alloys,are of great importance.In the present paper,we will focus on the effect of external factors,including pre-deformation,annealing,and high pressure annealing,on the magnetic transitions and the related magnetocaloric properties in Ni-Mn-Co-Sn ferromagnetic shape memory alloys.Our approaches and the main results in this particular field will be reviewed.
基金supported by National Key R&D Program of China(Grant No.2017YFB0702701)the National Natural Science Foundation of China(Grant No.51771091,51976149)the Young Elite Scientists Sponsorship Program by CAST under the grant No.2019QNRC001。
文摘1.Introduction Refrigeration plays an essential role in nowadays society.However,conventional refrigeration based on vapor compression cooling shows high energy consumption,complicated structure and even environmental pollution.Searching for an environmentalfriendly and energy-saving refrigeration technology has become a matter of concern[1,2].In the past few decades,the solid-state refrigeration technologies mainly represented by magnetocaloric effect(MCE),electrocaloric effect(ECE)and elastocaloric effect(e CE)have been regarded as promising candidate to replace traditional vapor compression refrigeration technology owing to environmental friendliness and high efficiency[1-9].
