近年来,过渡金属硫化物已成为锂离子电池理想的负极材料之一。其中,MoS_2具有的独特二维层状结构使得其能够让Li+在电化学反应中可逆地嵌入和脱出,且拥有较高的理论储锂容量(670 m A·h/g)而受到广泛关注。但MoS_2作为典型的半导体...近年来,过渡金属硫化物已成为锂离子电池理想的负极材料之一。其中,MoS_2具有的独特二维层状结构使得其能够让Li+在电化学反应中可逆地嵌入和脱出,且拥有较高的理论储锂容量(670 m A·h/g)而受到广泛关注。但MoS_2作为典型的半导体材料,电导率低下且在锂离子嵌入-脱出的过程中会发生较大程度的体积收缩膨胀,所以具有较差的倍率性能和循环性能,限制了其商业化的使用。很多研究通过优化MoS_2结构或与其它导电材料复合来克服上述缺陷。Co_9S_8具有较高的电导率,但由于其迟缓的离子传输动力学表现出低的首次库仑效率及较差的循环稳定性,基于此,将MoS_2与Co_9S_8结合利用二者协同效应来提高复合材料的电化学性能。本文采用溶剂热与气相沉积法制备得MoS_2@Co_9S_8蛋黄结构复合材料电极。MoS_2与Co_9S_8均匀分布于整个蛋黄壳结构,这有利于电子和锂离子的快速传输,从而有效地提升了电极的循环性能和倍率性能。其次,蛋黄壳的空穴有效缓解了在充放电过程中的体积膨胀,及其活性位点有效缩短了离子和电子的传输距离,提高了电极反应动力学并获得高比容量。MoS_2@Co_9S_8蛋黄壳复合物的循环性能与倍率性能在同等条件下均高于Co_9S_8和MoS_2,在电流密度为0.2 A/g下循环500圈后,放电容量仍能维持在631.5 m A·h/g。展开更多
Photocatalysis driven by near-infrared（NIR）light is of scientific and technological interest for ex-ploiting solar energy.In this study,we demonstrate a facile hydrothermal process to synthesize core-shell nanoparti...Photocatalysis driven by near-infrared（NIR）light is of scientific and technological interest for ex-ploiting solar energy.In this study,we demonstrate a facile hydrothermal process to synthesize core-shell nanoparticles combining upconversion nanoparticles（UCNPs）and alloyed ZnxCwhich can be excited using NIR or visible light.Morphologies,phase,and chemical composition have been investigated using field-emission scanning electron microscopy,transmission electron mi-croscopy,X-ray diffraction analysis,and atomic absorption spectroscopy.Moreover,we found that amorphous TiO2 layers existing in the final samples play an important role in formation ofyolk-shell nanoparticles,which bind the as-prepared ZnxCnanoparticlescan be tuna-ble by adjusting the amount of the Cd and Zn source compounds.The photochemical reduction of Cr（Ⅵ）in water has been performed to study the photocatalytic performance under irradiation by NIR light or a simulated solar light,showing efficient photoreduction and Cr（Ⅵ）removal over the/TiO2 yolk-shell nanoparticles.The as-prepared UCNPs@ZnxC/TiO2 nanoparticles show excellent production of hydroxyl radicals,which are responsible for the photochemical reduction of Cr（Ⅵ）to Cr（Ⅲ）.This study will provide an alternative strategy for en-vironmental wastewater treatment,making full use of solar energy.展开更多
Yolk‐shell structured nanoparticles are of immense scientific and technological interests because of their unique architecture and myriad of applications.This review summarizes recent progresses in the use of yolk‐s...Yolk‐shell structured nanoparticles are of immense scientific and technological interests because of their unique architecture and myriad of applications.This review summarizes recent progresses in the use of yolk‐shell structured nanoparticles as nanoreactors for various chemical reactions.A very brief overview of synthetic strategies is provided with emphasis on recent research progress in the last five years.Catalytic applications of these yolk‐shell structured nanoreactors are then discussed by covering photocatalysis,methane reforming and electrochemical conversion.The state of the art research and perspective in future development are also highlighted.展开更多
文摘近年来,过渡金属硫化物已成为锂离子电池理想的负极材料之一。其中,MoS_2具有的独特二维层状结构使得其能够让Li+在电化学反应中可逆地嵌入和脱出,且拥有较高的理论储锂容量(670 m A·h/g)而受到广泛关注。但MoS_2作为典型的半导体材料,电导率低下且在锂离子嵌入-脱出的过程中会发生较大程度的体积收缩膨胀,所以具有较差的倍率性能和循环性能,限制了其商业化的使用。很多研究通过优化MoS_2结构或与其它导电材料复合来克服上述缺陷。Co_9S_8具有较高的电导率,但由于其迟缓的离子传输动力学表现出低的首次库仑效率及较差的循环稳定性,基于此,将MoS_2与Co_9S_8结合利用二者协同效应来提高复合材料的电化学性能。本文采用溶剂热与气相沉积法制备得MoS_2@Co_9S_8蛋黄结构复合材料电极。MoS_2与Co_9S_8均匀分布于整个蛋黄壳结构,这有利于电子和锂离子的快速传输,从而有效地提升了电极的循环性能和倍率性能。其次,蛋黄壳的空穴有效缓解了在充放电过程中的体积膨胀,及其活性位点有效缩短了离子和电子的传输距离,提高了电极反应动力学并获得高比容量。MoS_2@Co_9S_8蛋黄壳复合物的循环性能与倍率性能在同等条件下均高于Co_9S_8和MoS_2,在电流密度为0.2 A/g下循环500圈后,放电容量仍能维持在631.5 m A·h/g。
基金supported by the National Natural Science Foundation of China (21471043, 51603059, 31501576)~~
文摘Photocatalysis driven by near-infrared（NIR）light is of scientific and technological interest for ex-ploiting solar energy.In this study,we demonstrate a facile hydrothermal process to synthesize core-shell nanoparticles combining upconversion nanoparticles（UCNPs）and alloyed ZnxCwhich can be excited using NIR or visible light.Morphologies,phase,and chemical composition have been investigated using field-emission scanning electron microscopy,transmission electron mi-croscopy,X-ray diffraction analysis,and atomic absorption spectroscopy.Moreover,we found that amorphous TiO2 layers existing in the final samples play an important role in formation ofyolk-shell nanoparticles,which bind the as-prepared ZnxCnanoparticlescan be tuna-ble by adjusting the amount of the Cd and Zn source compounds.The photochemical reduction of Cr（Ⅵ）in water has been performed to study the photocatalytic performance under irradiation by NIR light or a simulated solar light,showing efficient photoreduction and Cr（Ⅵ）removal over the/TiO2 yolk-shell nanoparticles.The as-prepared UCNPs@ZnxC/TiO2 nanoparticles show excellent production of hydroxyl radicals,which are responsible for the photochemical reduction of Cr（Ⅵ）to Cr（Ⅲ）.This study will provide an alternative strategy for en-vironmental wastewater treatment,making full use of solar energy.
文摘Yolk‐shell structured nanoparticles are of immense scientific and technological interests because of their unique architecture and myriad of applications.This review summarizes recent progresses in the use of yolk‐shell structured nanoparticles as nanoreactors for various chemical reactions.A very brief overview of synthetic strategies is provided with emphasis on recent research progress in the last five years.Catalytic applications of these yolk‐shell structured nanoreactors are then discussed by covering photocatalysis,methane reforming and electrochemical conversion.The state of the art research and perspective in future development are also highlighted.
