研究了一种基于超材料的光学太阳反射镜(optical solar reflector,OSR),其由掺铝氧化锌(AZO)超表面、MgF2介质层和Ag金属反射层三层结构组成。在热红外AZO超表面激发表面等离激元共振增强电磁吸收,MgF2介质层介电常数的稳定性减少了吸...研究了一种基于超材料的光学太阳反射镜(optical solar reflector,OSR),其由掺铝氧化锌(AZO)超表面、MgF2介质层和Ag金属反射层三层结构组成。在热红外AZO超表面激发表面等离激元共振增强电磁吸收,MgF2介质层介电常数的稳定性减少了吸收振荡带来的反射,在可见光照射下AZO超表面和MgF2介质层的透明特性可降低太阳辐射损耗,Ag金属反射层可有效抑制透射。仿真结果表明,优化后的OSR在0.3~2.5μm内有17.6%的低太阳吸收率,在2.5~30.0μm内有86.5%的高红外发射率。此外,偏振和入射角度对其性能影响较小。该结构在红外波段实现了较好的吸收,在红外热成像、辐射制冷等领域也具有潜在应用价值。展开更多
Biomass-derived hard carbons,usually prepared by pyrolysis,are widely considered the most promising anode materials for sodium-ion bat-teries(SIBs)due to their high capacity,low poten-tial,sustainability,cost-effectiv...Biomass-derived hard carbons,usually prepared by pyrolysis,are widely considered the most promising anode materials for sodium-ion bat-teries(SIBs)due to their high capacity,low poten-tial,sustainability,cost-effectiveness,and environ-mental friendliness.The pyrolysis method affects the microstructure of the material,and ultimately its so-dium storage performance.Our previous work has shown that pyrolysis in a sealed graphite vessel im-proved the sodium storage performance of the car-bon,however the changes in its microstructure and the way this influences the sodium storage are still unclear.A series of hard carbon materials derived from corncobs(CCG-T,where T is the pyrolysis temperature)were pyrolyzed in a sealed graphite vessel at different temperatures.As the pyrolysis temperature increased from 1000 to 1400℃ small carbon domains gradually transformed into long and curved domains.At the same time,a greater number of large open pores with uniform apertures,as well as more closed pores,were formed.With the further increase of pyrolysis temperature to 1600℃,the long and curved domains became longer and straighter,and some closed pores gradually became open.CCG-1400,with abundant closed pores,had a superior SIB performance,with an initial reversible ca-pacity of 320.73 mAh g^(-1) at a current density of 30 mA g^(-1),an initial Coulomb efficiency(ICE)of 84.34%,and a capacity re-tention of 96.70%after 100 cycles.This study provides a method for the precise regulation of the microcrystalline and pore structures of hard carbon materials.展开更多
Preparation of highly active hydrodesulfurization catalysts is extremely meaningful for the sulfur removal from thiophene substances.In this work,commercial nano-Al_(2)O_(3)with mesoporous structure supported monometa...Preparation of highly active hydrodesulfurization catalysts is extremely meaningful for the sulfur removal from thiophene substances.In this work,commercial nano-Al_(2)O_(3)with mesoporous structure supported monometallic phosphide(NiP/Al_(2)O_(3)and MoP/Al_(2)O_(3))and bimetallic phosphide(NiMoP/Al_(2)O_(3)with various Ni/Mo molar ratio)catalysts are successfully prepared by temperature-programmed reduction.X-ray diffraction(XRD)result shows the Ni/Mo molar ratio affect the crystal phase in catalysts.Scanning electron microscopy(SEM),transmission electron microscopy(TEM)and X-ray photoelectron spectroscopy(XPS)characterizations co-confirm the interact between Ni and Mo elements in bimetallic phosphide.Catalyst evaluation in hydrodesulfurization of dibenzothiophene shows that bimetallic phosphide samples exhibit better catalytic performance than monometallic phosphide.62.1%conversion and 86.3%biphenyl selectivity with 30 h stability are achieved over NiMoP/Al_(2)O_(3)(Ni/Mo=1∶1)catalyst at 400℃under 3 MPa H_(2).All characterization results demonstrate that the improved activity of bimetallic phosphide owes to the Ni-Mo synergistic effect in NiMoP/Al_(2)O_(3)(Ni/Mo=1∶1)catalyst.This finding provides a guide to the design of bimetallic catalyst with synergistic effect.展开更多
文摘研究了一种基于超材料的光学太阳反射镜(optical solar reflector,OSR),其由掺铝氧化锌(AZO)超表面、MgF2介质层和Ag金属反射层三层结构组成。在热红外AZO超表面激发表面等离激元共振增强电磁吸收,MgF2介质层介电常数的稳定性减少了吸收振荡带来的反射,在可见光照射下AZO超表面和MgF2介质层的透明特性可降低太阳辐射损耗,Ag金属反射层可有效抑制透射。仿真结果表明,优化后的OSR在0.3~2.5μm内有17.6%的低太阳吸收率,在2.5~30.0μm内有86.5%的高红外发射率。此外,偏振和入射角度对其性能影响较小。该结构在红外波段实现了较好的吸收,在红外热成像、辐射制冷等领域也具有潜在应用价值。
文摘Biomass-derived hard carbons,usually prepared by pyrolysis,are widely considered the most promising anode materials for sodium-ion bat-teries(SIBs)due to their high capacity,low poten-tial,sustainability,cost-effectiveness,and environ-mental friendliness.The pyrolysis method affects the microstructure of the material,and ultimately its so-dium storage performance.Our previous work has shown that pyrolysis in a sealed graphite vessel im-proved the sodium storage performance of the car-bon,however the changes in its microstructure and the way this influences the sodium storage are still unclear.A series of hard carbon materials derived from corncobs(CCG-T,where T is the pyrolysis temperature)were pyrolyzed in a sealed graphite vessel at different temperatures.As the pyrolysis temperature increased from 1000 to 1400℃ small carbon domains gradually transformed into long and curved domains.At the same time,a greater number of large open pores with uniform apertures,as well as more closed pores,were formed.With the further increase of pyrolysis temperature to 1600℃,the long and curved domains became longer and straighter,and some closed pores gradually became open.CCG-1400,with abundant closed pores,had a superior SIB performance,with an initial reversible ca-pacity of 320.73 mAh g^(-1) at a current density of 30 mA g^(-1),an initial Coulomb efficiency(ICE)of 84.34%,and a capacity re-tention of 96.70%after 100 cycles.This study provides a method for the precise regulation of the microcrystalline and pore structures of hard carbon materials.
基金supported by National Natural Science Foundation of China(22202093)the Scientific and Technological Innovation Youth Talent Team of Shanxi Province(202204051001005)。
文摘Preparation of highly active hydrodesulfurization catalysts is extremely meaningful for the sulfur removal from thiophene substances.In this work,commercial nano-Al_(2)O_(3)with mesoporous structure supported monometallic phosphide(NiP/Al_(2)O_(3)and MoP/Al_(2)O_(3))and bimetallic phosphide(NiMoP/Al_(2)O_(3)with various Ni/Mo molar ratio)catalysts are successfully prepared by temperature-programmed reduction.X-ray diffraction(XRD)result shows the Ni/Mo molar ratio affect the crystal phase in catalysts.Scanning electron microscopy(SEM),transmission electron microscopy(TEM)and X-ray photoelectron spectroscopy(XPS)characterizations co-confirm the interact between Ni and Mo elements in bimetallic phosphide.Catalyst evaluation in hydrodesulfurization of dibenzothiophene shows that bimetallic phosphide samples exhibit better catalytic performance than monometallic phosphide.62.1%conversion and 86.3%biphenyl selectivity with 30 h stability are achieved over NiMoP/Al_(2)O_(3)(Ni/Mo=1∶1)catalyst at 400℃under 3 MPa H_(2).All characterization results demonstrate that the improved activity of bimetallic phosphide owes to the Ni-Mo synergistic effect in NiMoP/Al_(2)O_(3)(Ni/Mo=1∶1)catalyst.This finding provides a guide to the design of bimetallic catalyst with synergistic effect.
