Fan-shaped SiO2 nanowires modified SiO2@C composites with a bio-inspired hierarchical porous structure and a high accessible surface area were prepared by in situ molten salt template method.The combination of biogeni...Fan-shaped SiO2 nanowires modified SiO2@C composites with a bio-inspired hierarchical porous structure and a high accessible surface area were prepared by in situ molten salt template method.The combination of biogenic hierarchical porous structure and one-dimensional nanostructure with similar features was successfully obtained by one-pot heat treatment in the presence of rice husk SiO2 with SiO2 acting as precursor and ZnCl2 acting as molten salt and growth template.A large amount of fan-shaped SiO2 nanowires with numerous tiny branches sprouting from the central nanowires were grown in the inter-porous epidermis and on the surface of rice husk SiO2 for temperatures up to 1200 ℃.The in situ ZnCl2 molten salt template base-growth mechanism is responsible for the initial formation of SiO2/ZnCl2 co-melting nanowires and the subsequent growth of fan-shaped SiO2 nanowires.The as-prepared samples have been successfully employed as organic absorbers with high efficiency in the field of wastewater treatment.展开更多
Solid-phase extraction method has proven efficient and amenable to microchips.A novel DNA purification microchip was demonstrated using porous silicon dioxide as the solid phase matrix.Porous SiO_2 was coated on the w...Solid-phase extraction method has proven efficient and amenable to microchips.A novel DNA purification microchip was demonstrated using porous silicon dioxide as the solid phase matrix.Porous SiO_2 was coated on the wall of the channel of the microchip to provide a surface-enlarging matrix.The porous silicon was achieved by anodisation of the silicon reactor in a HF/ethanol mixture and then was oxidized thermally at a lower increasing/decreasing rate to form porous SiO_2.Through optimization of the preparing conditions a more stable microchip was established.Compared with the microchip without the porous layer,the microchip with the porous SiO_2 layer achieved higher extracted efficiency of DNA.Genomic DNA from rat whole blood could be extracted and purified in 35 minutes.展开更多
Porous Y 2SiO 5 ceramic is a promising high-temperature thermal insulator in harsh environment.However,all the published relevant works faced serious problems,such as severe linear shrinkage,low porosity and low stren...Porous Y 2SiO 5 ceramic is a promising high-temperature thermal insulator in harsh environment.However,all the published relevant works faced serious problems,such as severe linear shrinkage,low porosity and low strength.In this study,porous Y 2SiO 5 ceramic with low sintering shrinkage and high porosity was successfully prepared by foam-gelcasting method using gelatin as the gelling agent.The effects of sintering methods,including in situ reaction sintering and direct sintering,and sintering temperatures on the phase composition,microstructure,shrinkage,porosity,and compressive strength of porous Y 2SiO 5were investigated.Compared with samples fabricated by direct sintering,porous Y 2SiO 5 ceramic prepared via in situ reaction sintering method has the merits of the low linear shrinkage of 1.0%-4.7%,low bulk density of 0.79-0.88 g/cm^3,high porosity of 82.1%-80.1%,and high strength of 3.54-8.03 MPa,when the sintering temperatures increase from 1350 to 1550 ℃.Porous Y 2SiO 5 has unique multiple pore structures,especially containing the interconnected small pores in skeleton.The thermal conductivity of porous Y 2SiO 5 is very low,which is 0.228 W/（m·K） for the sample with a porosity of 79.6%.This work reports an optimal processing method of highly porous Y 2SiO 5 with the potential application as high-temperature thermal insulation material.展开更多
A new method for fabricating ordered porous silicon is reported. A two-dimensional silica nanosphere array is used as a template with a hydrofluoric acid-hydrogen peroxide solution for etching the nanospheres. The ini...A new method for fabricating ordered porous silicon is reported. A two-dimensional silica nanosphere array is used as a template with a hydrofluoric acid-hydrogen peroxide solution for etching the nanospheres. The initial diameter and distribution of the holes in the resulting porous silicon layer are determined by the size and distribution of the silica nanospheres. The corrosion time can be used to control the depths of the holes. It is found that the presence of a SiO2 layer, formed by the oxidation of the rough internal surface of the hole, is the primary reason allowing the corrosion to proceed. Ultraviolet reflection and thermal conductivity measurements show that the diameter and distribution of the holes have a great influence on properties of the porous silicon.展开更多
Chromatographic substrate material,as a carrier of chromatographic stationary phases,plays a vital role in defining its chromatographic characteristics,including column efficiency,stability,peak capacity and so on.In ...Chromatographic substrate material,as a carrier of chromatographic stationary phases,plays a vital role in defining its chromatographic characteristics,including column efficiency,stability,peak capacity and so on.In recent years,superficially porous silica(SPS)was widely valued for its excellent performance in improving the column efficiency due to its special structural properties,which was considered as a real substitute for fully porous SiO_(2)(FPS)and had been used to develop a new generation of highly efficient stationary phase.To help researchers better understand the SPS and further promote its application and development in the field of chromatography,the rapid separation mechanism,preparation method and its applications in the rapid separation and analysis of enantiomers were systematically introduced,and the development prospects of SPS were also prospected in this paper.展开更多
Positron annihilation lifetime and Doppler broadening of annihilation line techniques have been used to obtain information about the small pore structure and size of porous SiO2 thin film produced by sputtered Al-Si t...Positron annihilation lifetime and Doppler broadening of annihilation line techniques have been used to obtain information about the small pore structure and size of porous SiO2 thin film produced by sputtered Al-Si thin film and etched Al-Si thin film. The film is prepared by an Al/Si 75：25 at.-% （A175Si25） target with the radiofrequency （RF） power of 66 W at room temperature. A 5 wt.-% phosphoric acid solution is used to etch the Al cylinders. All the A1 cylinders dissolved in the solution after 15 h at room temperature, and the sample is subsequently rinsed in pure water. In this way, the porous SiO2 on the Si substrate is produced. From our results, the values of all lifetime components in the spectra of Al-Si thin film are less than 1 ns, but the value of one of the lifetime components in the spectra of porous SiO2 thin film is τ = 7.80 ns. With these values of lifetime, RTE （Rectangular Pore Extension） model has been used to analyze the pore size.展开更多
基金financially supported by the Key Technology R and D Program of Hubei Province(No.2015BCA253)the China Postdoctoral Science Foundation(No.2015M572210)the Open Foundation of The State Key Laboratory of Refractories and Metallurgy(No.2014QN17)
文摘Fan-shaped SiO2 nanowires modified SiO2@C composites with a bio-inspired hierarchical porous structure and a high accessible surface area were prepared by in situ molten salt template method.The combination of biogenic hierarchical porous structure and one-dimensional nanostructure with similar features was successfully obtained by one-pot heat treatment in the presence of rice husk SiO2 with SiO2 acting as precursor and ZnCl2 acting as molten salt and growth template.A large amount of fan-shaped SiO2 nanowires with numerous tiny branches sprouting from the central nanowires were grown in the inter-porous epidermis and on the surface of rice husk SiO2 for temperatures up to 1200 ℃.The in situ ZnCl2 molten salt template base-growth mechanism is responsible for the initial formation of SiO2/ZnCl2 co-melting nanowires and the subsequent growth of fan-shaped SiO2 nanowires.The as-prepared samples have been successfully employed as organic absorbers with high efficiency in the field of wastewater treatment.
基金The authors greatly acknowledge the financial support from the National Science Foundation of China under Grant number 20299030, 60427001 and 60501020.
文摘Solid-phase extraction method has proven efficient and amenable to microchips.A novel DNA purification microchip was demonstrated using porous silicon dioxide as the solid phase matrix.Porous SiO_2 was coated on the wall of the channel of the microchip to provide a surface-enlarging matrix.The porous silicon was achieved by anodisation of the silicon reactor in a HF/ethanol mixture and then was oxidized thermally at a lower increasing/decreasing rate to form porous SiO_2.Through optimization of the preparing conditions a more stable microchip was established.Compared with the microchip without the porous layer,the microchip with the porous SiO_2 layer achieved higher extracted efficiency of DNA.Genomic DNA from rat whole blood could be extracted and purified in 35 minutes.
基金supported by the National Natural Science Foundation of China under Grant Nos.51032006 and 51372252
文摘Porous Y 2SiO 5 ceramic is a promising high-temperature thermal insulator in harsh environment.However,all the published relevant works faced serious problems,such as severe linear shrinkage,low porosity and low strength.In this study,porous Y 2SiO 5 ceramic with low sintering shrinkage and high porosity was successfully prepared by foam-gelcasting method using gelatin as the gelling agent.The effects of sintering methods,including in situ reaction sintering and direct sintering,and sintering temperatures on the phase composition,microstructure,shrinkage,porosity,and compressive strength of porous Y 2SiO 5were investigated.Compared with samples fabricated by direct sintering,porous Y 2SiO 5 ceramic prepared via in situ reaction sintering method has the merits of the low linear shrinkage of 1.0%-4.7%,low bulk density of 0.79-0.88 g/cm^3,high porosity of 82.1%-80.1%,and high strength of 3.54-8.03 MPa,when the sintering temperatures increase from 1350 to 1550 ℃.Porous Y 2SiO 5 has unique multiple pore structures,especially containing the interconnected small pores in skeleton.The thermal conductivity of porous Y 2SiO 5 is very low,which is 0.228 W/（m·K） for the sample with a porosity of 79.6%.This work reports an optimal processing method of highly porous Y 2SiO 5 with the potential application as high-temperature thermal insulation material.
基金Supported by the National Natural Science Foundation of China under Grant Nos 10804026 and 51101049the Natural Science Foundation of Hebei Province under Grant Nos A2013205101 and A2014205051the Hebei Talent Cultivation Foundation under Grant No A201400119
文摘A new method for fabricating ordered porous silicon is reported. A two-dimensional silica nanosphere array is used as a template with a hydrofluoric acid-hydrogen peroxide solution for etching the nanospheres. The initial diameter and distribution of the holes in the resulting porous silicon layer are determined by the size and distribution of the silica nanospheres. The corrosion time can be used to control the depths of the holes. It is found that the presence of a SiO2 layer, formed by the oxidation of the rough internal surface of the hole, is the primary reason allowing the corrosion to proceed. Ultraviolet reflection and thermal conductivity measurements show that the diameter and distribution of the holes have a great influence on properties of the porous silicon.
基金financially supported by the National Natural Science Foundation of China(21822407,22074154)Xinjiang“Tianshan Youth Plan”Project(No.2017Q027)+1 种基金the“Light of West China”Program from Chinese Academy of Sciencethe Gansu Province Basic Research Innovation Group Program(20JR5RA573)
文摘Chromatographic substrate material,as a carrier of chromatographic stationary phases,plays a vital role in defining its chromatographic characteristics,including column efficiency,stability,peak capacity and so on.In recent years,superficially porous silica(SPS)was widely valued for its excellent performance in improving the column efficiency due to its special structural properties,which was considered as a real substitute for fully porous SiO_(2)(FPS)and had been used to develop a new generation of highly efficient stationary phase.To help researchers better understand the SPS and further promote its application and development in the field of chromatography,the rapid separation mechanism,preparation method and its applications in the rapid separation and analysis of enantiomers were systematically introduced,and the development prospects of SPS were also prospected in this paper.
基金Supported by National Natural Science Foundation of China (10575112, 60606011)
文摘Positron annihilation lifetime and Doppler broadening of annihilation line techniques have been used to obtain information about the small pore structure and size of porous SiO2 thin film produced by sputtered Al-Si thin film and etched Al-Si thin film. The film is prepared by an Al/Si 75：25 at.-% （A175Si25） target with the radiofrequency （RF） power of 66 W at room temperature. A 5 wt.-% phosphoric acid solution is used to etch the Al cylinders. All the A1 cylinders dissolved in the solution after 15 h at room temperature, and the sample is subsequently rinsed in pure water. In this way, the porous SiO2 on the Si substrate is produced. From our results, the values of all lifetime components in the spectra of Al-Si thin film are less than 1 ns, but the value of one of the lifetime components in the spectra of porous SiO2 thin film is τ = 7.80 ns. With these values of lifetime, RTE （Rectangular Pore Extension） model has been used to analyze the pore size.
