The fabrication of a new type of one-dimensional Au-Ag porous nanotube（NPT） structure was presented based on a facile combination of nanocrystal growth and surface modification.Ag nanowires with various diameters we...The fabrication of a new type of one-dimensional Au-Ag porous nanotube（NPT） structure was presented based on a facile combination of nanocrystal growth and surface modification.Ag nanowires with various diameters were firstly served as the chemical plating templates via a polyol-process.Then,one-dimensional（1D） Au-Ag porous nanostructures with tailored structural features could be prepared by controlling the individual steps involved in this process,such as nanowire growth,surface modification,thermal diffusion,and dealloying.Structural characterizations reveal these Au-Ag porous nanotubes,non-porous nanotubes and porous nanowires possess novel nano-architectures with multimodal open porosity and excellent structural continuity and integrity,which make them particularly desirable as novel 1D nanocarriers for biomedical,drug delivery and sensing applications.展开更多
Bacterial infections,especially the frequently emerging "superbugs",seriously affect the quality of human life and even threaten human health.As the emerging antimicrobial agents that effectively eradicate p...Bacterial infections,especially the frequently emerging "superbugs",seriously affect the quality of human life and even threaten human health.As the emerging antimicrobial agents that effectively eradicate pathogens,nanomaterials have been widely explored due to their effectiveness against wide-spectrum bacteria and“superbugs”.Of them,Ag/AgX nanostructures(X representing Cl,Br or I)have emerged as an excellent antibacterial agent because of their excellent photocatalytic performance in inactivating pathogens under light irradiation,which provides a new opportunity for the development of high-efficient visible-light driven photocatalytic sterilization.To date,Ag/AgX nanostructures have been widely employed in antibacterial associated fields because they are efficient in producing reactive oxygen species(ROS)and reactive chlorine species(RCS)under visible light irradiation.In this review,we summarized the recent progress of Ag/AgX nanostructures as plasmonic photocatalysts in the antibacterial field,focusing on the antibacterial effects and mechanisms of Ag/AgX nanostructures,as well as their potent applications.Finally,the challenges and prospects of Ag/AgX nanostructures acting as active antibacterial agents were discussed.展开更多
In this study,hierarchical Ag/La2 O2 CO3 micro/nanostructures(MNSs)were synthesized by in situ loading Ag nanoparticles(NPs)on the surface of the La2 O2 CO3 MNSs.The prepared La2 O2 CO3 MNSs present flower-like shape ...In this study,hierarchical Ag/La2 O2 CO3 micro/nanostructures(MNSs)were synthesized by in situ loading Ag nanoparticles(NPs)on the surface of the La2 O2 CO3 MNSs.The prepared La2 O2 CO3 MNSs present flower-like shape and can be tuned by the molar ratio of La(NO3)3 and CO(NH2)2.In the molar ratio of 1:2 to 1:55,the La2 O2 CO3 MNSs mainly consist of polyhedral rods,irregular rods and irregular spindles and their size is about 10,8 and 7μm,respectively.After loading Ag NPs,the spindle-like Ag/La2 O2 CO3 MNSs were used for phosphate removal and antibacterial activity.At the initial phosphate concentration of20 mg/L,the removal rate is 59.6%.The Ag/La2 O2 CO3 MNSs have significant antibacterial activity and their MIC values for S.aureus and E.coli are 31.3 and 15.6μg/mL,respectively.The results indicate that Ag/La2 O2 CO3 MNSs may have good application prospects in open water to inhibit bacterial growth.展开更多
Diesel soot subjected to high exhaust temperature suffers from thermal ageing,which is difficult to be removed by regeneration process.Based on the thermogravimetric(TG)analysis and images by high resolution transmiss...Diesel soot subjected to high exhaust temperature suffers from thermal ageing,which is difficult to be removed by regeneration process.Based on the thermogravimetric(TG)analysis and images by high resolution transmission electron microscope(HRTEM),effects of thermal ageing temperature,ageing time and oxygen concentration on oxidation characteristic of soot are investigated.The activation energy of soot increases with the increase of ageing temperature and oxygen concentration.The activation energy increases rapidly when the ageing time is less than 45 min,and then it keeps in a value of 157 kJ/mol when the ageing time is between 45 and 60 min.Compared to the soot without thermal ageing,the shape of ageing soot particles presents shorter diameter and more regular circle by observing soot nanostructure.With the increase of ageing temperature,ageing time and oxygen concentration,the more stable structure of“shell and core”is shown in the basic carbon.The soot has an increased fringe length,decreased tortuosity and separation distance after thermal ageing process,which leads to the deepening of the disorder degree of soot nanostructures and reduction of soot oxidation activity.Consequently,the thermal ageing process should be avoided in order to optimize the active regeneration strategy.展开更多
Silver(Ag) nanostructures demonstrate outstanding optical, electrical, magnetic, and catalytic properties and are utilized in photonic, energy, sensors, and biomedical devices.The target application and the performanc...Silver(Ag) nanostructures demonstrate outstanding optical, electrical, magnetic, and catalytic properties and are utilized in photonic, energy, sensors, and biomedical devices.The target application and the performance can be inherently tuned by control of configuration, shape, and size of Ag nanostructures. In this work, we demonstrate the systematical fabrication of various configurations of Ag nanostructures on sapphire(0001) by controlling the Ag deposition thickness at different annealing environments in a plasma ion coater. In particular, the evolution of Ag particles(between 2 and 20 nm),irregular nanoclusters(between 30 and 60 nm), and nanocluster networks(between 80 and 200 nm) are found be depended on the thickness of Ag thin film. The results were systematically analyzed and explained based on the solid-state dewetting,surface diffusion, Volmer–Weber growth model, coalescence,and surface energy minimization mechanism. The growth behavior of Ag nanostructures is remarkably differentiated at higher annealing temperature(750 ℃) due to the sublimation and temperature-dependent characteristic of dewetting process.In addition, Raman and reflectance spectra analyses reveal that optical properties of Ag nanostructures depend on their morphology.展开更多
The change of the temperature coefficient of resistivity (a) with the particle size, dp, and the grain size, dc, in the nanostructured Ag bulk samples was investigated. dp and dc were controlled by heating the nano-Ag...The change of the temperature coefficient of resistivity (a) with the particle size, dp, and the grain size, dc, in the nanostructured Ag bulk samples was investigated. dp and dc were controlled by heating the nano-Ag powders over the temperature range from 393 to 453 K. The electrical resistance measurements of the nanostructured Ag bulk samples obtained by compacting the Ag powders after heat treatments showed a change in the sign of a with dP and dc. When dp and dc are smaller or equal to 18 and 11 nm below room temperature or 20 and 12 nm above room temperature, respectively, the sign of the temperature coefficient of resistivity changes from positive to negative. The negative a arises mainly from the high resistivity induced by the particle interfaces with very lowly ordered or even disordered structure, a large volume fraction of interfaces and impurities existing in the interfaces, and the quantum size effect appearing in the nano-Ag grains.展开更多
In this study, Ag2ZnGeO4 flower-like hierarchical nanostructure was prepared using a simple and mild method. The as-prepared samples were characterized with X-ray diffraction, scanning electron micros- copy, transmiss...In this study, Ag2ZnGeO4 flower-like hierarchical nanostructure was prepared using a simple and mild method. The as-prepared samples were characterized with X-ray diffraction, scanning electron micros- copy, transmission electron microscopy, energy dispersive X-ray spectroscopy, UV-vis diffuse reflectance spectroscopy, X-ray photoelectron spectroscopy, and N2 adsorption and desorption isotherms. Mean- while, the photocatalytic activity of the as-prepared samples was explored using Rhodamine B as a model pollutant, The results indicated that the Ag2ZnGeO4 hierarchical nanostructures obtained consisted of nanoplates and nanurods, and adopted spherical flower-like morphology. Moreover, the as-prepared Ag2ZnGeO4 hierarchical nanostructure was an efficient and stable visible-light photocatalyst for the deg- radation of organic dyes in water. After visible light irradiation for 105 rain, the degradation of Rhodamine B was up to 92%. Moreover, the photocatalytic activity of Ag2ZnGeO4 remained unchanged after three successive cycles,展开更多
A facile sonochemical method was developed to synthesize metallic Ag spherical nanoparticles on the surface of ZnWO4 nanorods by forming heterostructure Ag/ZnWO4 nanocomposites.The Ag/ZnWO4 nanocomposites were charact...A facile sonochemical method was developed to synthesize metallic Ag spherical nanoparticles on the surface of ZnWO4 nanorods by forming heterostructure Ag/ZnWO4 nanocomposites.The Ag/ZnWO4 nanocomposites were characterized by X-ray powder diffraction (XRD),Fourier transform infrared spectroscopy (FTIR),field emission scanning electron microscopy (FESEM),transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS).The experimental results showed that fcc metallic Ag nanoparticles were supported on surface of monoclinic sanmartinite ZnWO4 nanorods.The Ag 3d3/2 and Ag 3d5/2 peaks have well-separated binding energies of 6.00 eV,certifying the existence of metallic Ag.The Ag/ZnWO4 nanocomposites were evaluated for photodegradation of methylene blue (MB) induced by ultraviolet-visible (UV-Vis) radiation.In this research,heterostructure 10 wt% Ag nanoparticle/ZnWO4-nanorod composites have the highest photocatalytic activity of 99% degradation of MB within 60 min.The increase in photocatalytic activity was the result of photoinduced electrons in conduction band of ZnWO4 that effectively diffused to metallic Ag spherical nanoparticles and the inhibition of electron-hole recombination process.展开更多
Although lithium metal and sodium metal are promised as ideal anodes for lithium ion batteries(LIBs)and sodium ion batteries(SIBs),they still suffer from inevitable dendrite growth.In light of this,silver nanoparticle...Although lithium metal and sodium metal are promised as ideal anodes for lithium ion batteries(LIBs)and sodium ion batteries(SIBs),they still suffer from inevitable dendrite growth.In light of this,silver nanoparticles(Ag NPs)are sputtered onto three-dimensional carbon nanotube decorated graphene foam(3D CNT-GF)to construct superior 3D Ag/CNT-GF composite matrix for lithium metal anodes(LMAs)and sodium metal anodes(SMAs).With this design,lithiophilic/sodiophilic Ag NPs could provide favorable sites to guide Li/Na metal nucleation and growth,thus leading to low nucleation overpotentials,high Coulombic efficiency and long cycle performance.Accordingly,3D Ag/CNT-GF electrodes can stably cy-cle for 1000 and 750 cycles at 3 mA cm^(−2)with 1 mAh cm^(−2)for SMAs and LMAs,respectively.More attractively,it can also stably sustain 300 cycles(SMAs)and 500 cycles(LMAs)at a large current den-sity of 5 mA cm^(−2)with 1 mAh cm^(−2).The excellent electrochemical performance can be attributed to the lithiophilic/sodiophilic electrode surface,3D porous electrode structure and the dendrite-free mor-phology as demonstrated by ex-situ scanning electron microscopy(SEM)and in-situ optical microscopy analyses.Furthermore,full cells based on Na@3D Ag/CNT-GF||Na 3 V 2(PO 4)3@carbon(NVP@C)and Li@3D Ag/CNT-GF||LiFePO 4(LFP)could deliver highly reversible capacities of 90.1 and 106.4 mAh g^(−1),respec-tively,at 100 mA g^(−1)after 200 cycles for SIBs and LIBs,respectively.This work demonstrates a novel 3D Ag/CNT-GF matrix for boosting Li/Na deposition stability for their future applications.展开更多
基金Project (2012CB932800) supported by the National Basic Research Program of ChinaProject (2012M521330) supported by China Postdoctoral Science Foundation
文摘The fabrication of a new type of one-dimensional Au-Ag porous nanotube（NPT） structure was presented based on a facile combination of nanocrystal growth and surface modification.Ag nanowires with various diameters were firstly served as the chemical plating templates via a polyol-process.Then,one-dimensional（1D） Au-Ag porous nanostructures with tailored structural features could be prepared by controlling the individual steps involved in this process,such as nanowire growth,surface modification,thermal diffusion,and dealloying.Structural characterizations reveal these Au-Ag porous nanotubes,non-porous nanotubes and porous nanowires possess novel nano-architectures with multimodal open porosity and excellent structural continuity and integrity,which make them particularly desirable as novel 1D nanocarriers for biomedical,drug delivery and sensing applications.
基金This work was financially supported by the National Natural Science Foundation of China(Nos.21304044,51663019 and 22062017)the Natural Science Foundation of Inner Mongolia Autonomous Region(Nos.2015MS0520,2019JQ03 and 2019BS02004)+2 种基金the State Key Laboratory of Medicinal Chemical Biology(Nos.201603006 and 2018051)the State Key Laboratory of Polymer Physics and Chemistry(No.2018-08)the Program of Higher-Level Talents of Inner Mongolia University(No.30105-125136).
文摘Bacterial infections,especially the frequently emerging "superbugs",seriously affect the quality of human life and even threaten human health.As the emerging antimicrobial agents that effectively eradicate pathogens,nanomaterials have been widely explored due to their effectiveness against wide-spectrum bacteria and“superbugs”.Of them,Ag/AgX nanostructures(X representing Cl,Br or I)have emerged as an excellent antibacterial agent because of their excellent photocatalytic performance in inactivating pathogens under light irradiation,which provides a new opportunity for the development of high-efficient visible-light driven photocatalytic sterilization.To date,Ag/AgX nanostructures have been widely employed in antibacterial associated fields because they are efficient in producing reactive oxygen species(ROS)and reactive chlorine species(RCS)under visible light irradiation.In this review,we summarized the recent progress of Ag/AgX nanostructures as plasmonic photocatalysts in the antibacterial field,focusing on the antibacterial effects and mechanisms of Ag/AgX nanostructures,as well as their potent applications.Finally,the challenges and prospects of Ag/AgX nanostructures acting as active antibacterial agents were discussed.
基金Project supported by the National Natural Science Foundation of China(21271062)。
文摘In this study,hierarchical Ag/La2 O2 CO3 micro/nanostructures(MNSs)were synthesized by in situ loading Ag nanoparticles(NPs)on the surface of the La2 O2 CO3 MNSs.The prepared La2 O2 CO3 MNSs present flower-like shape and can be tuned by the molar ratio of La(NO3)3 and CO(NH2)2.In the molar ratio of 1:2 to 1:55,the La2 O2 CO3 MNSs mainly consist of polyhedral rods,irregular rods and irregular spindles and their size is about 10,8 and 7μm,respectively.After loading Ag NPs,the spindle-like Ag/La2 O2 CO3 MNSs were used for phosphate removal and antibacterial activity.At the initial phosphate concentration of20 mg/L,the removal rate is 59.6%.The Ag/La2 O2 CO3 MNSs have significant antibacterial activity and their MIC values for S.aureus and E.coli are 31.3 and 15.6μg/mL,respectively.The results indicate that Ag/La2 O2 CO3 MNSs may have good application prospects in open water to inhibit bacterial growth.
基金Project(51676167)supported by the National Natural Science Foundation of ChinaProject(17TD0035)supported by the Sichuan Provincial Scientific Research Innovation Team Program,ChinaProjects(2017TD0026,2015TD0021)supported by Science&Technology Department of Sichuan Province,China。
文摘Diesel soot subjected to high exhaust temperature suffers from thermal ageing,which is difficult to be removed by regeneration process.Based on the thermogravimetric(TG)analysis and images by high resolution transmission electron microscope(HRTEM),effects of thermal ageing temperature,ageing time and oxygen concentration on oxidation characteristic of soot are investigated.The activation energy of soot increases with the increase of ageing temperature and oxygen concentration.The activation energy increases rapidly when the ageing time is less than 45 min,and then it keeps in a value of 157 kJ/mol when the ageing time is between 45 and 60 min.Compared to the soot without thermal ageing,the shape of ageing soot particles presents shorter diameter and more regular circle by observing soot nanostructure.With the increase of ageing temperature,ageing time and oxygen concentration,the more stable structure of“shell and core”is shown in the basic carbon.The soot has an increased fringe length,decreased tortuosity and separation distance after thermal ageing process,which leads to the deepening of the disorder degree of soot nanostructures and reduction of soot oxidation activity.Consequently,the thermal ageing process should be avoided in order to optimize the active regeneration strategy.
基金the National Research Foundation of Korea(no.2011-0030079 and 2016R1A1A1A05005009)the research grant of Kwangwoon University in 2016
文摘Silver(Ag) nanostructures demonstrate outstanding optical, electrical, magnetic, and catalytic properties and are utilized in photonic, energy, sensors, and biomedical devices.The target application and the performance can be inherently tuned by control of configuration, shape, and size of Ag nanostructures. In this work, we demonstrate the systematical fabrication of various configurations of Ag nanostructures on sapphire(0001) by controlling the Ag deposition thickness at different annealing environments in a plasma ion coater. In particular, the evolution of Ag particles(between 2 and 20 nm),irregular nanoclusters(between 30 and 60 nm), and nanocluster networks(between 80 and 200 nm) are found be depended on the thickness of Ag thin film. The results were systematically analyzed and explained based on the solid-state dewetting,surface diffusion, Volmer–Weber growth model, coalescence,and surface energy minimization mechanism. The growth behavior of Ag nanostructures is remarkably differentiated at higher annealing temperature(750 ℃) due to the sublimation and temperature-dependent characteristic of dewetting process.In addition, Raman and reflectance spectra analyses reveal that optical properties of Ag nanostructures depend on their morphology.
基金the National Natural Science FOundation of China under grant! No.19974041the National Major Fundamental ResearCh Program-Nal
文摘The change of the temperature coefficient of resistivity (a) with the particle size, dp, and the grain size, dc, in the nanostructured Ag bulk samples was investigated. dp and dc were controlled by heating the nano-Ag powders over the temperature range from 393 to 453 K. The electrical resistance measurements of the nanostructured Ag bulk samples obtained by compacting the Ag powders after heat treatments showed a change in the sign of a with dP and dc. When dp and dc are smaller or equal to 18 and 11 nm below room temperature or 20 and 12 nm above room temperature, respectively, the sign of the temperature coefficient of resistivity changes from positive to negative. The negative a arises mainly from the high resistivity induced by the particle interfaces with very lowly ordered or even disordered structure, a large volume fraction of interfaces and impurities existing in the interfaces, and the quantum size effect appearing in the nano-Ag grains.
基金financially supported by the Open Project of Beijing National Laboratory for Molecular Sciences(No.20140163)the Shanghai Municipal Education Commission(Plateau Discipline Construction Program)the National Natural Science Foundation of China(No.21301118)
文摘In this study, Ag2ZnGeO4 flower-like hierarchical nanostructure was prepared using a simple and mild method. The as-prepared samples were characterized with X-ray diffraction, scanning electron micros- copy, transmission electron microscopy, energy dispersive X-ray spectroscopy, UV-vis diffuse reflectance spectroscopy, X-ray photoelectron spectroscopy, and N2 adsorption and desorption isotherms. Mean- while, the photocatalytic activity of the as-prepared samples was explored using Rhodamine B as a model pollutant, The results indicated that the Ag2ZnGeO4 hierarchical nanostructures obtained consisted of nanoplates and nanurods, and adopted spherical flower-like morphology. Moreover, the as-prepared Ag2ZnGeO4 hierarchical nanostructure was an efficient and stable visible-light photocatalyst for the deg- radation of organic dyes in water. After visible light irradiation for 105 rain, the degradation of Rhodamine B was up to 92%. Moreover, the photocatalytic activity of Ag2ZnGeO4 remained unchanged after three successive cycles,
基金financial support through the contact No. SCI610022S, and Center of Excellence in Materials Science and Technology, Chiang Mai University under the administration of Materials Science Research Center, Faculty of Science, Chiang Mai University, Thailand
文摘A facile sonochemical method was developed to synthesize metallic Ag spherical nanoparticles on the surface of ZnWO4 nanorods by forming heterostructure Ag/ZnWO4 nanocomposites.The Ag/ZnWO4 nanocomposites were characterized by X-ray powder diffraction (XRD),Fourier transform infrared spectroscopy (FTIR),field emission scanning electron microscopy (FESEM),transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS).The experimental results showed that fcc metallic Ag nanoparticles were supported on surface of monoclinic sanmartinite ZnWO4 nanorods.The Ag 3d3/2 and Ag 3d5/2 peaks have well-separated binding energies of 6.00 eV,certifying the existence of metallic Ag.The Ag/ZnWO4 nanocomposites were evaluated for photodegradation of methylene blue (MB) induced by ultraviolet-visible (UV-Vis) radiation.In this research,heterostructure 10 wt% Ag nanoparticle/ZnWO4-nanorod composites have the highest photocatalytic activity of 99% degradation of MB within 60 min.The increase in photocatalytic activity was the result of photoinduced electrons in conduction band of ZnWO4 that effectively diffused to metallic Ag spherical nanoparticles and the inhibition of electron-hole recombination process.
基金supported by the National Natural Science Foun-dation of China(Grant No.U1804132)Zhongyuan Youth Talent Support Program of Henan Province(Grant No.ZYQR201912152)Academic Improvement Program of Physics of Zhengzhou Univer-sity(GrantNo.2018WLTJ02),Zhengzhou University Youth Talent Start-up Grant.
文摘Although lithium metal and sodium metal are promised as ideal anodes for lithium ion batteries(LIBs)and sodium ion batteries(SIBs),they still suffer from inevitable dendrite growth.In light of this,silver nanoparticles(Ag NPs)are sputtered onto three-dimensional carbon nanotube decorated graphene foam(3D CNT-GF)to construct superior 3D Ag/CNT-GF composite matrix for lithium metal anodes(LMAs)and sodium metal anodes(SMAs).With this design,lithiophilic/sodiophilic Ag NPs could provide favorable sites to guide Li/Na metal nucleation and growth,thus leading to low nucleation overpotentials,high Coulombic efficiency and long cycle performance.Accordingly,3D Ag/CNT-GF electrodes can stably cy-cle for 1000 and 750 cycles at 3 mA cm^(−2)with 1 mAh cm^(−2)for SMAs and LMAs,respectively.More attractively,it can also stably sustain 300 cycles(SMAs)and 500 cycles(LMAs)at a large current den-sity of 5 mA cm^(−2)with 1 mAh cm^(−2).The excellent electrochemical performance can be attributed to the lithiophilic/sodiophilic electrode surface,3D porous electrode structure and the dendrite-free mor-phology as demonstrated by ex-situ scanning electron microscopy(SEM)and in-situ optical microscopy analyses.Furthermore,full cells based on Na@3D Ag/CNT-GF||Na 3 V 2(PO 4)3@carbon(NVP@C)and Li@3D Ag/CNT-GF||LiFePO 4(LFP)could deliver highly reversible capacities of 90.1 and 106.4 mAh g^(−1),respec-tively,at 100 mA g^(−1)after 200 cycles for SIBs and LIBs,respectively.This work demonstrates a novel 3D Ag/CNT-GF matrix for boosting Li/Na deposition stability for their future applications.
