This paper explores the capability of the“surface-protected etching”process for the creation of rattle-type SiO_(2)@void@SiO_(2) colloidal structures featuring a mesoporous silica shell and a mesoporous movable sili...This paper explores the capability of the“surface-protected etching”process for the creation of rattle-type SiO_(2)@void@SiO_(2) colloidal structures featuring a mesoporous silica shell and a mesoporous movable silica core.The surface-protected etching process involves stabilization of the particle surface using a polymer ligand,and then selective etching of the interior to form hollow structures.In this paper,this strategy has been extended to the formation of rattle-like structures by etching SiO_(2)@SiO_(2) core shell particles which are synthesized by a two-step sol gel process.The key is to introduce a protecting polymer of polyvinylpyrrolidone(PVP)to the surface of both core and shell in order to tailor their relative stability against chemical etching.Upon reacting with NaOH,the outer layer silica becomes a hollow shell as only the surface layer is protected by PVP and the interior is removed,while the core remains its original size thanks to the protection of PVP on its surface.This process can be carried out at room temperature without the need of additional templates or complicated heterogeneous coating procedures.The etching process also results in the rattle-type colloids having mesoscale pores with two distinct average sizes.In our demonstration of a model drug delivery process,such mesoporous structures show an interesting two-step elution profile which is believed to be related to the unique porous rattle structures.展开更多
In the present day,there is a growing trend of employing new strategies to synthesize hybrid nanoparticles,which involve combining various functionalities into a single nanocomposite system.These modern methods differ...In the present day,there is a growing trend of employing new strategies to synthesize hybrid nanoparticles,which involve combining various functionalities into a single nanocomposite system.These modern methods differ significantly from the traditional classical approaches and have emerged at the forefront of materials science.The fabrication of hybrid nanomaterials presents an unparalleled opportunity for applica-tions in a wide range of areas,including therapy to diagnosis.The focus of this review article is to shed light on the different modalities of hybrid nanoparticles,providing a concise description of hybrid silver nano-particles,exploring various modes of synthesis and classification of hybrid silver nanoparticles,and highlighting their advantages.Addi-tionally,we discussed core-shell silver nanoparticles and various types of core and shell combinations based on the material category,such as dielectric,metal,or semiconductor.The two primary classes of hybrid silver nanoparticles were also reviewed.Furthermore,various hybrid nanoparticles and their methods of synthesis were discussed but we emphasize silica as a suitable candidate for hybridization alongside metal nanoparticles.This choice is due to its hydrophilic surface qualities and high surface charge,which provide the desired repulsive forces to minimize aggregation between the metal nanoparticles in the liquid solution.Silica shell encapsulation also provides chemical inertness,robustness and the adaptability to the desired hybrid nanoparticle.Therefore,among all the materials used to coat metal nanoparticles;silica is highly approved.展开更多
Fragmentation/disassembly of fiber-like micelles generated by living crystalline-driven self-assembly(CDSA)is usually encountered in aqueous media,which hinders the applications of micelles.Herein,we report the genera...Fragmentation/disassembly of fiber-like micelles generated by living crystalline-driven self-assembly(CDSA)is usually encountered in aqueous media,which hinders the applications of micelles.Herein,we report the generation of uniform fiber-like micelles consisting of a𝜋Л-conjugated oligo(p-phenylenevinylene)core and a crosslinking silica shell with grafted poly(ethylene glycol)(PEG)chains by the combination of living CDSA,silica chemistry and surface grafting-onto strategy.Owing to the presence of crosslinking silica shell and the outmost PEG chains,the resulting micelles exhibit excellent dispersity and colloidal stability in PBS buffer,BSA aqueous solution and upon heating at 80℃ for 2 h without micellar fragmentation/disassembly.The micelles also show negligible cytotoxicity toward both HeLa cervical cancer and HEK239T human embryonic kidney cell lines.Interestingly,micelles with Ln of 156 nm show the“stealth”property with no significant uptake by HeLa cells,whereas some certain amounts of micelles with Ln of 535 nm can penetrate into HeLa cells,showing length-dependent cellular uptake behaviors.These results provide a route to prepare uniform,colloidally stable fiber-like nanostructures with tunable length and functions derived for biomedical applications.展开更多
A one-step ultrasonic mechanical method was used to synthesize a kind of atmospheric water harvesting material with high water harvesting performance in a wide relative humidity(RH)range,especially at low RH(RH<40%...A one-step ultrasonic mechanical method was used to synthesize a kind of atmospheric water harvesting material with high water harvesting performance in a wide relative humidity(RH)range,especially at low RH(RH<40%),namely,mesoporous silica capsule(MSC)with core-shell structure.Transmission electron microscopy(TEM),nitrogen adsorption and other characterization techniques were used to study the formation process of nano-microspheres.A new mechanism of self-adaptive concentration gradient regulation of silicon migration and recombination core-shell structure was proposed to explain the formation of a cavity in the MSC system.The core-shell design can enhance the specific surface area and pore volume while maintaining the monodispersity and mesoporous size.To study the water harvesting performance of MSC,solid silica nanoparticles(SSN)and mesoporous silica nanoparticles(MSN)were prepared.In a small atmospheric water collection test(25℃,40%RH),the water vapour adsorption and desorption kinetics of MSC,SSN,MSN and a commercial silica gel(CSG)were compared and analyzed.The results show that the MSC with mesoporous channels and core-shell structure can provide about 0.324 gwater/gadsorbent,79%higher than the CSG(0.181 gwater/gadsorbent).It is 25.1%higher than that of 0.259 gwater/gadsorbentof un-hollowed MSN and 980%higher than that of0.03 gwater/gadsorbentof un-hollowed SSN.The material has a large specific surface area and pore volume,simple preparation method and low cost,which provides a feasible idea for realising atmospheric water collection in arid and semi-arid regions.展开更多
Regulating the surface plasmon resonance(SPR)of metallic nanostructures is of great interests for optical and catalytic applications,however,it is still a great challenge for tuning SPR features of small metallic nano...Regulating the surface plasmon resonance(SPR)of metallic nanostructures is of great interests for optical and catalytic applications,however,it is still a great challenge for tuning SPR features of small metallic nanoparticles(<10 nm).In this work,we design a unique dielectric support-urchin-like mesoporous silica nanoparticles(U-SiO_(2))with ordered long spikes on its surface,which can well enhance the SPR properties of~3 nm gold nanocrystals(AuNCs).The U-SiO_(2)not only realizes the uniform self-assembly of AuNCs,but also prevents their aggregation due to the unique confinement effect.The finite-difference time-domain simulations show that the AuNCs on U-SiO_(2)can generate plasmonic hot spots with highly enhanced electromagnetic field.Moreover,the hot electrons can be effectively and rapidly transferred through the interface junction to TiO_(2).Thus,a high visible-light-driven photocatalytic activity can be observed,which is 3.8 times higher than that of smooth photocatalysts.The concept of dielectric supports engineering provides a new strategy for tuning SPR of small metallic nanocrystals towards the development of advanced plasmon-based applications.展开更多
The silica coated aluminum composite particles were prepared by hydrolysis–condensation polymerization of tetraethylorthosilicate(TEOS)on the surface of aluminum particle.The structure,morphology,and properties of th...The silica coated aluminum composite particles were prepared by hydrolysis–condensation polymerization of tetraethylorthosilicate(TEOS)on the surface of aluminum particle.The structure,morphology,and properties of the silica coated aluminum were studied.The peaks of Si—O—Si are presented in the Fourier transform infrared(FT-IR)spectrum of the composite particles.The thickness of the silica shell is about 80 nm according to the results of transmission electron microscopy(TEM)and laser particle size analysis,while the mean diameter of the aluminum particle is 7.13μm.The mass fraction of silica in the sample was determined by fluorescent X-ray spectrometry(XRF).Result of the thermogravimetric analysis(TGA)indicates that thermal stability of silica coated aluminum particles is better than that of pure aluminum particles at low temperature while more reactive at high temperature.展开更多
采用改进的两步法在原位基础上合成了以纳米零价铁(nano Zero Valent Iron,nZVI)为核芯的核壳型介孔二氧化硅(nZVI@mesoSiO_2).同时,通过简单地调控铁源用量得到具有单一nZVI核芯和不同壳层厚度的核壳型纳米复合材料.结果发现,铁源用量...采用改进的两步法在原位基础上合成了以纳米零价铁(nano Zero Valent Iron,nZVI)为核芯的核壳型介孔二氧化硅(nZVI@mesoSiO_2).同时,通过简单地调控铁源用量得到具有单一nZVI核芯和不同壳层厚度的核壳型纳米复合材料.结果发现,铁源用量的增加会导致核芯尺寸减小、壳层厚度增加及颗粒比表面积下降.当铁源用量为2.78 g时,得到的nZVI@mesoSiO_2不仅具有较高的比表面积和单一且均匀的孔径分布,而且对2,4,6-三氯苯酚(2,4,6-Trichlorophenol, 2,4,6-TCP)的去除表现出很高的性能.影响因素实验表明,材料的最佳投加量为1.0 g·L^(-1),体系适宜初始pH为5.0,污染物初始浓度升高会导致去除效果下降,并且反应体系内乙二胺四乙酸(EDTA)的存在可以提高2,4,6-TCP的去除率.材料的重复利用实验结果表明,经过多次循环反应后会导致材料nZVI核芯的失活和孔道的堵塞.本研究不仅为制备可控壳层厚度的核壳型介孔材料提供了理论指导,而且为进一步改性合成对2,4,6-TP具有高选择性的复合材料提供了依据.展开更多
In this work,the effects of pH value of waste water and initial concentration of phosphorus on dephosphorization materials were investigated.The materials were prepared by shaping,sintering and hydrothermal reshaping ...In this work,the effects of pH value of waste water and initial concentration of phosphorus on dephosphorization materials were investigated.The materials were prepared by shaping,sintering and hydrothermal reshaping oyster shell and silica micro-powder.Different concentrations of phosphorus-contained waste water were simulated with potassium dihydrogen phosphate solution,the effect of dephosphorization was tested with phosphomolybdenum blue spectrophotometer method,and the crystal phase and microstructure of materials were characterized by XRD and SEM methods. It was indicated that dephosphorization was completed in 6 h when the initial phosphorus concentration in waste water was lower than 15 mg/L, and the dephosphorization time prolonged as the increase of phosphorus concentration. It was observed that the pH value of waste water influenced dephosphorization significantly, and neutral subalkalic environment favored dephosphorization. When the pH value was 11, the efficiency of dephosphozation was the greatest. For waste water with an initial concentration of 20 mg/L, the dephosphozation rate is close to 100% in8 h.展开更多
Silica and montmorillonite-supported silica nanoparticles were prepared via an acid one step sol-gel process. The synthesized solids were characterized using XRD, FTIR, TEM and N2 adsorption. The effect of preparing t...Silica and montmorillonite-supported silica nanoparticles were prepared via an acid one step sol-gel process. The synthesized solids were characterized using XRD, FTIR, TEM and N2 adsorption. The effect of preparing temperatures on the structure and properties of the silica nanoparticles were studied. The results show that the increase of annealing temperature from 25 to 200℃, don’t change amorphous state of silica. While for montmorillonite-supported silica the clay platelets are delaminated during the sol-gel process. TEM results showed that the average particle size of silica is increased by increasing temperature due to the particle sintering and the clay-silica nanoparticles possessed core–shell morphology with diameter of 29 nm. The surface area measurements showed that by increasing annealing temperature the surface area was decreased due to aggregation of particle. The clay-silica sample showed lower average pore width than that of the silica prepared at 200℃ indicating that it has a macropores structure. The adsorption efficiency of the prepared samples was tested by adsorption of protoporphyrin IX. The highest adsorption efficiency was found for SiO2 prepared at 200℃. Temkin model describe the equilibrium of adsorption of protoporphyrin IX on caly-silica nanoparticles under different conditions.展开更多
文摘This paper explores the capability of the“surface-protected etching”process for the creation of rattle-type SiO_(2)@void@SiO_(2) colloidal structures featuring a mesoporous silica shell and a mesoporous movable silica core.The surface-protected etching process involves stabilization of the particle surface using a polymer ligand,and then selective etching of the interior to form hollow structures.In this paper,this strategy has been extended to the formation of rattle-like structures by etching SiO_(2)@SiO_(2) core shell particles which are synthesized by a two-step sol gel process.The key is to introduce a protecting polymer of polyvinylpyrrolidone(PVP)to the surface of both core and shell in order to tailor their relative stability against chemical etching.Upon reacting with NaOH,the outer layer silica becomes a hollow shell as only the surface layer is protected by PVP and the interior is removed,while the core remains its original size thanks to the protection of PVP on its surface.This process can be carried out at room temperature without the need of additional templates or complicated heterogeneous coating procedures.The etching process also results in the rattle-type colloids having mesoscale pores with two distinct average sizes.In our demonstration of a model drug delivery process,such mesoporous structures show an interesting two-step elution profile which is believed to be related to the unique porous rattle structures.
文摘In the present day,there is a growing trend of employing new strategies to synthesize hybrid nanoparticles,which involve combining various functionalities into a single nanocomposite system.These modern methods differ significantly from the traditional classical approaches and have emerged at the forefront of materials science.The fabrication of hybrid nanomaterials presents an unparalleled opportunity for applica-tions in a wide range of areas,including therapy to diagnosis.The focus of this review article is to shed light on the different modalities of hybrid nanoparticles,providing a concise description of hybrid silver nano-particles,exploring various modes of synthesis and classification of hybrid silver nanoparticles,and highlighting their advantages.Addi-tionally,we discussed core-shell silver nanoparticles and various types of core and shell combinations based on the material category,such as dielectric,metal,or semiconductor.The two primary classes of hybrid silver nanoparticles were also reviewed.Furthermore,various hybrid nanoparticles and their methods of synthesis were discussed but we emphasize silica as a suitable candidate for hybridization alongside metal nanoparticles.This choice is due to its hydrophilic surface qualities and high surface charge,which provide the desired repulsive forces to minimize aggregation between the metal nanoparticles in the liquid solution.Silica shell encapsulation also provides chemical inertness,robustness and the adaptability to the desired hybrid nanoparticle.Therefore,among all the materials used to coat metal nanoparticles;silica is highly approved.
基金The authors are thankful for financial support from National Science Foundation for Distinguished Young Scholars(51825304)National Natural Science Foundation of China(52122314,51873229 and 51961145103)+3 种基金the project of Bureau of International Cooperation,CAS(121731KYSB20200006)Youth Innovation Promotion Association of CAS(Y2020062)Shanghai Scientific and Technological Innovation Project(19ZR1468400,19590750400,20JC1415400 and 21520780100)Innovation Program of Shanghai Municipal Education Commission(2019-01-07-00-05-E00012).
文摘Fragmentation/disassembly of fiber-like micelles generated by living crystalline-driven self-assembly(CDSA)is usually encountered in aqueous media,which hinders the applications of micelles.Herein,we report the generation of uniform fiber-like micelles consisting of a𝜋Л-conjugated oligo(p-phenylenevinylene)core and a crosslinking silica shell with grafted poly(ethylene glycol)(PEG)chains by the combination of living CDSA,silica chemistry and surface grafting-onto strategy.Owing to the presence of crosslinking silica shell and the outmost PEG chains,the resulting micelles exhibit excellent dispersity and colloidal stability in PBS buffer,BSA aqueous solution and upon heating at 80℃ for 2 h without micellar fragmentation/disassembly.The micelles also show negligible cytotoxicity toward both HeLa cervical cancer and HEK239T human embryonic kidney cell lines.Interestingly,micelles with Ln of 156 nm show the“stealth”property with no significant uptake by HeLa cells,whereas some certain amounts of micelles with Ln of 535 nm can penetrate into HeLa cells,showing length-dependent cellular uptake behaviors.These results provide a route to prepare uniform,colloidally stable fiber-like nanostructures with tunable length and functions derived for biomedical applications.
基金the National Natural Science Foundation of China(No.50772131)the National High-tech R&D Program of China(863 Program)(No.2011AA322100)+1 种基金the Key Project of Chinese Ministry of Education(No.106086)the Fundamental Research Funds for the Central Universities(No.2010YJ05)。
文摘A one-step ultrasonic mechanical method was used to synthesize a kind of atmospheric water harvesting material with high water harvesting performance in a wide relative humidity(RH)range,especially at low RH(RH<40%),namely,mesoporous silica capsule(MSC)with core-shell structure.Transmission electron microscopy(TEM),nitrogen adsorption and other characterization techniques were used to study the formation process of nano-microspheres.A new mechanism of self-adaptive concentration gradient regulation of silicon migration and recombination core-shell structure was proposed to explain the formation of a cavity in the MSC system.The core-shell design can enhance the specific surface area and pore volume while maintaining the monodispersity and mesoporous size.To study the water harvesting performance of MSC,solid silica nanoparticles(SSN)and mesoporous silica nanoparticles(MSN)were prepared.In a small atmospheric water collection test(25℃,40%RH),the water vapour adsorption and desorption kinetics of MSC,SSN,MSN and a commercial silica gel(CSG)were compared and analyzed.The results show that the MSC with mesoporous channels and core-shell structure can provide about 0.324 gwater/gadsorbent,79%higher than the CSG(0.181 gwater/gadsorbent).It is 25.1%higher than that of 0.259 gwater/gadsorbentof un-hollowed MSN and 980%higher than that of0.03 gwater/gadsorbentof un-hollowed SSN.The material has a large specific surface area and pore volume,simple preparation method and low cost,which provides a feasible idea for realising atmospheric water collection in arid and semi-arid regions.
基金This work was supported by the National Key Research and Development Program of China(No.2018YFE0201701)the National Natural Science Foundation of China(Nos.21975050,21905052,11975081,and 22105041)+3 种基金Science and Technology Commission of Shanghai Municipality(No.21ZR1408800)Key Basic Research Program of Science and Technology Commission of Shanghai Municipality(No.19JC1410700)the Program of Shanghai Academic Research Leader(No.21XD1420800)Guangdong Basic and Applied Basic Research Foundation(No.2021A1515010108).
文摘Regulating the surface plasmon resonance(SPR)of metallic nanostructures is of great interests for optical and catalytic applications,however,it is still a great challenge for tuning SPR features of small metallic nanoparticles(<10 nm).In this work,we design a unique dielectric support-urchin-like mesoporous silica nanoparticles(U-SiO_(2))with ordered long spikes on its surface,which can well enhance the SPR properties of~3 nm gold nanocrystals(AuNCs).The U-SiO_(2)not only realizes the uniform self-assembly of AuNCs,but also prevents their aggregation due to the unique confinement effect.The finite-difference time-domain simulations show that the AuNCs on U-SiO_(2)can generate plasmonic hot spots with highly enhanced electromagnetic field.Moreover,the hot electrons can be effectively and rapidly transferred through the interface junction to TiO_(2).Thus,a high visible-light-driven photocatalytic activity can be observed,which is 3.8 times higher than that of smooth photocatalysts.The concept of dielectric supports engineering provides a new strategy for tuning SPR of small metallic nanocrystals towards the development of advanced plasmon-based applications.
基金Project(50306008)supported by the National Natural Science Foundation of China
文摘The silica coated aluminum composite particles were prepared by hydrolysis–condensation polymerization of tetraethylorthosilicate(TEOS)on the surface of aluminum particle.The structure,morphology,and properties of the silica coated aluminum were studied.The peaks of Si—O—Si are presented in the Fourier transform infrared(FT-IR)spectrum of the composite particles.The thickness of the silica shell is about 80 nm according to the results of transmission electron microscopy(TEM)and laser particle size analysis,while the mean diameter of the aluminum particle is 7.13μm.The mass fraction of silica in the sample was determined by fluorescent X-ray spectrometry(XRF).Result of the thermogravimetric analysis(TGA)indicates that thermal stability of silica coated aluminum particles is better than that of pure aluminum particles at low temperature while more reactive at high temperature.
基金Supported by Fujian Science and Technology Administration (2004I003 and 20060037)
文摘In this work,the effects of pH value of waste water and initial concentration of phosphorus on dephosphorization materials were investigated.The materials were prepared by shaping,sintering and hydrothermal reshaping oyster shell and silica micro-powder.Different concentrations of phosphorus-contained waste water were simulated with potassium dihydrogen phosphate solution,the effect of dephosphorization was tested with phosphomolybdenum blue spectrophotometer method,and the crystal phase and microstructure of materials were characterized by XRD and SEM methods. It was indicated that dephosphorization was completed in 6 h when the initial phosphorus concentration in waste water was lower than 15 mg/L, and the dephosphorization time prolonged as the increase of phosphorus concentration. It was observed that the pH value of waste water influenced dephosphorization significantly, and neutral subalkalic environment favored dephosphorization. When the pH value was 11, the efficiency of dephosphozation was the greatest. For waste water with an initial concentration of 20 mg/L, the dephosphozation rate is close to 100% in8 h.
文摘Silica and montmorillonite-supported silica nanoparticles were prepared via an acid one step sol-gel process. The synthesized solids were characterized using XRD, FTIR, TEM and N2 adsorption. The effect of preparing temperatures on the structure and properties of the silica nanoparticles were studied. The results show that the increase of annealing temperature from 25 to 200℃, don’t change amorphous state of silica. While for montmorillonite-supported silica the clay platelets are delaminated during the sol-gel process. TEM results showed that the average particle size of silica is increased by increasing temperature due to the particle sintering and the clay-silica nanoparticles possessed core–shell morphology with diameter of 29 nm. The surface area measurements showed that by increasing annealing temperature the surface area was decreased due to aggregation of particle. The clay-silica sample showed lower average pore width than that of the silica prepared at 200℃ indicating that it has a macropores structure. The adsorption efficiency of the prepared samples was tested by adsorption of protoporphyrin IX. The highest adsorption efficiency was found for SiO2 prepared at 200℃. Temkin model describe the equilibrium of adsorption of protoporphyrin IX on caly-silica nanoparticles under different conditions.
