Transition metals and their oxide materials have been widely employed to fabricate superhydrophobic surfaces, not only because of their surface topography with controllable microstructures leading to water-repellence,...Transition metals and their oxide materials have been widely employed to fabricate superhydrophobic surfaces, not only because of their surface topography with controllable microstructures leading to water-repellence, diverse adhesion even tun- able wettability, but also due to a variety of special properties like optical performance, magnetism, anti-bacterial, transparency and so on. At the meantime, biomimetic superhydrophobic surfaces have attracted great interest from fabricating hierarchical micro-/nano-structures inspired by nature to imitate creature＇s properties and many potential applications, including self-cleaning, antifogging, antireflection, low drag and great stability and durability. In this review, natural surfaces and biomimetic materials with special wettability are introduced by classification according to the similar microstructure of mor- phology, like array structure, sheet overlapped structure, high density hairs and seta shaped structure. Not only do we exhibit their special performances, but also try to find out the true reasons behind the phenomenon. Then, the recent progress of a series of superhydrophobic transition mental and their oxide materials, including TiO2, ZnO, Fe304, CuO, Ag, Au and so on, is pre- sented with a focus on fabricating methods, microstructures, wettability, and other properties. As followed, these superhydro- phobic surfaces can be applied in many fields, such as oil/water separation, self-cleaning, photo-controlled reversible wet- tability, surface-enhanced Raman scattering, antibacterial, anticorrosion, and synthesis of various applications. However, few of them have been applied in practical life. Hence, we discuss the remaining challenges at present and the development tendency in future at the end of this article. This review aims to present recent development of transition metals and their oxides applied in biomimetic superhydrophobic surfaces about fabrication, microstructure, water repellence, various properties, and potential applications.展开更多
Cerium zirconium-based(CZ) oxygen storage materials(OSMs) play a crucial role in three-way catalysts(TWCs),while CZ needs to be modified to satisfy more rigorous emission standard.In this study,transition metal(TMs=Mn...Cerium zirconium-based(CZ) oxygen storage materials(OSMs) play a crucial role in three-way catalysts(TWCs),while CZ needs to be modified to satisfy more rigorous emission standard.In this study,transition metal(TMs=Mn,Cr,Fe,Cu) oxides modified CZ were prepared by incipient wetness impregnation method to improve the oxygen storage capacity of CZ-based materials.To clearly illustrate the influence of TM oxides,N2 adsorption-desorption,X-ray diffraction(XRD),oxygen storage capacity(OSC),temperature programmed reduction by H2(H2-TPR) and X-ray photoelectron spectroscopy(XPS) were used to characterize the physical and chemical properties of samples.It is found that,all modified CZ have higher OSC,lower reduction temperatures than those of pristine CZ.Interaction between TMOs and CZ take precedence over specific surface to influence OSC.Notably,FeOx/CZ has the highest OSC,which is about 1.9 times that of CZ and it could be attributed to synergistic effect between FeOx and CZ;CuOx/CZ has the lowest reduction temperature which is 168℃lower than that of CZ,and it can be explained by hydrogen spillover effect.展开更多
Atmospheric humic-like substances （HULIS） are not only an unresolved mixture of macro- organic compounds but also powerful chelating agents in atmospheric particulate matters （PMs）; impacting on both the propertie...Atmospheric humic-like substances （HULIS） are not only an unresolved mixture of macro- organic compounds but also powerful chelating agents in atmospheric particulate matters （PMs）; impacting on both the properties of aerosol particles and health effects by generating reactive oxygen spedes （ROS）. Currently, the interests of HULIS are intensively shifting to the investigations of HULIS-metal synergic effects and kinetics modeling studies, as well as the development of HULIS quantification, findings of possible HULIS sources and generation of ROS from HULIS. In light of HULIS studies, we comprehensively review the current knowledge of isolation and physicochemical characterization of HULIS from atmospheric samples as well as HULIS properties （hygroscopic, surface activity, and colloidal） and possible sources of HULIS. This review mainly highlights the generation of reactive oxygen species （ROS） from PMs, HULIS and transition metals, especially iron. This review also summarized the mechanism of iron-organic complexation and recent findings of OH formation from HULIS-metal complexes. This review will be helpful to carry out the modeling studies that concern with HULIS-transition metals and for further studies in the generation of ROS from HULIS-metal complexes,展开更多
基金This work is supported by the National Nature Science Foundation of China （Nos. 51522510 and 51675513）, and the National 973 Project （No. 2013CB632300）.
文摘Transition metals and their oxide materials have been widely employed to fabricate superhydrophobic surfaces, not only because of their surface topography with controllable microstructures leading to water-repellence, diverse adhesion even tun- able wettability, but also due to a variety of special properties like optical performance, magnetism, anti-bacterial, transparency and so on. At the meantime, biomimetic superhydrophobic surfaces have attracted great interest from fabricating hierarchical micro-/nano-structures inspired by nature to imitate creature＇s properties and many potential applications, including self-cleaning, antifogging, antireflection, low drag and great stability and durability. In this review, natural surfaces and biomimetic materials with special wettability are introduced by classification according to the similar microstructure of mor- phology, like array structure, sheet overlapped structure, high density hairs and seta shaped structure. Not only do we exhibit their special performances, but also try to find out the true reasons behind the phenomenon. Then, the recent progress of a series of superhydrophobic transition mental and their oxide materials, including TiO2, ZnO, Fe304, CuO, Ag, Au and so on, is pre- sented with a focus on fabricating methods, microstructures, wettability, and other properties. As followed, these superhydro- phobic surfaces can be applied in many fields, such as oil/water separation, self-cleaning, photo-controlled reversible wet- tability, surface-enhanced Raman scattering, antibacterial, anticorrosion, and synthesis of various applications. However, few of them have been applied in practical life. Hence, we discuss the remaining challenges at present and the development tendency in future at the end of this article. This review aims to present recent development of transition metals and their oxides applied in biomimetic superhydrophobic surfaces about fabrication, microstructure, water repellence, various properties, and potential applications.
基金supported by the National Key Research and Development Program(2017YFC0211002).
文摘Cerium zirconium-based(CZ) oxygen storage materials(OSMs) play a crucial role in three-way catalysts(TWCs),while CZ needs to be modified to satisfy more rigorous emission standard.In this study,transition metal(TMs=Mn,Cr,Fe,Cu) oxides modified CZ were prepared by incipient wetness impregnation method to improve the oxygen storage capacity of CZ-based materials.To clearly illustrate the influence of TM oxides,N2 adsorption-desorption,X-ray diffraction(XRD),oxygen storage capacity(OSC),temperature programmed reduction by H2(H2-TPR) and X-ray photoelectron spectroscopy(XPS) were used to characterize the physical and chemical properties of samples.It is found that,all modified CZ have higher OSC,lower reduction temperatures than those of pristine CZ.Interaction between TMOs and CZ take precedence over specific surface to influence OSC.Notably,FeOx/CZ has the highest OSC,which is about 1.9 times that of CZ and it could be attributed to synergistic effect between FeOx and CZ;CuOx/CZ has the lowest reduction temperature which is 168℃lower than that of CZ,and it can be explained by hydrogen spillover effect.
基金the Natural Science Foundation of China under NSFC Grant No. 21477073, 41273127 for support to conduct this research
文摘Atmospheric humic-like substances （HULIS） are not only an unresolved mixture of macro- organic compounds but also powerful chelating agents in atmospheric particulate matters （PMs）; impacting on both the properties of aerosol particles and health effects by generating reactive oxygen spedes （ROS）. Currently, the interests of HULIS are intensively shifting to the investigations of HULIS-metal synergic effects and kinetics modeling studies, as well as the development of HULIS quantification, findings of possible HULIS sources and generation of ROS from HULIS. In light of HULIS studies, we comprehensively review the current knowledge of isolation and physicochemical characterization of HULIS from atmospheric samples as well as HULIS properties （hygroscopic, surface activity, and colloidal） and possible sources of HULIS. This review mainly highlights the generation of reactive oxygen species （ROS） from PMs, HULIS and transition metals, especially iron. This review also summarized the mechanism of iron-organic complexation and recent findings of OH formation from HULIS-metal complexes. This review will be helpful to carry out the modeling studies that concern with HULIS-transition metals and for further studies in the generation of ROS from HULIS-metal complexes,
