Silver sulfide nanocrystals were successfully prepared by γ irradiation in water and ethanol systems, respectively, at an ambient pressure and room temperature. Sodium thiosulfate, thiourea and carbon disulfide were ...Silver sulfide nanocrystals were successfully prepared by γ irradiation in water and ethanol systems, respectively, at an ambient pressure and room temperature. Sodium thiosulfate, thiourea and carbon disulfide were employed as the sulfur ion source. The products were characterized by some means including X ray powder diffraction(XRD) , transmission electron microscopy(TEM) and X ray photoelectron energy spectrum(XPS). The result of the experiments indicated that the kind of the solvent and the sulfur ion source had influence on the size of silver sulfide nanoparticles. An interesting phenomenon was found in the TEM image of sampleⅡ: several long rods existed in the product and a tubular structure could be seen in one of these rods. The formation of this kind of special structure could be relevant to the coordination between thiourea and silver in water system.展开更多
In recent years much attention has been devoted to AgCl emulsion owing to its se-rial advantages and inimitable potential. But in the research of this emulsion a thorny problem remains unsolved till now, which is the ...In recent years much attention has been devoted to AgCl emulsion owing to its se-rial advantages and inimitable potential. But in the research of this emulsion a thorny problem remains unsolved till now, which is the improvement in sensitivity is always accompanied with high fog density. In this work 5 nm Ag2S particles were prepared and used as novel sensitizers in AgCl cubic and {100} tabular microcrystal emulsions. The novel sensitizer shows an effective sensitizing ability for silver chloride emulsion, and it is superior to the traditional Na2S2O3 sensi-tizer because by using it comparatively high sensitivity can be obtained with lower fog density. So the above sensitizing problem is going to be effectively solved. To discover the evolution mechanism of the sensitizer clusters and explain their excellent sensitizing properties, diffuse reflectance spectroscopy (DRS) was used as a probe on the AgCl microcrystal surface.展开更多
Porous Ag2S sensitized TiO2 catalysts were synthesized by the hydrothermal process.The crystallization and porous structure of the Ag2S/TiO2 composite photocatalysts were investigated by X-ray diffraction,scanning ele...Porous Ag2S sensitized TiO2 catalysts were synthesized by the hydrothermal process.The crystallization and porous structure of the Ag2S/TiO2 composite photocatalysts were investigated by X-ray diffraction,scanning electron microscopy with energy dispersive X-ray analysis,UV-Vis diffuse reflectance spectroscopy,and N2 adsorption.The Ag2S/TiO2 composites were mainly composed of anatase TiO2 and acanthite Ag2S.The absorption edge wavelengths of TiO2 and the Ag2S/TiO2 composite prepared with 3 mmol Na2S.5H2O were 400 and 800 nm,respectively,that is,the absorption edge of the composite had a pronounced red shift.The photocatalytic activity under visible light was investigated by the degradation of methylene blue with a UV-Vis spectrophotometer.The photocatalytic activities under visible light of the Ag2S/TiO2 photocatalysts were much higher than that of TiO2.展开更多
文摘Silver sulfide nanocrystals were successfully prepared by γ irradiation in water and ethanol systems, respectively, at an ambient pressure and room temperature. Sodium thiosulfate, thiourea and carbon disulfide were employed as the sulfur ion source. The products were characterized by some means including X ray powder diffraction(XRD) , transmission electron microscopy(TEM) and X ray photoelectron energy spectrum(XPS). The result of the experiments indicated that the kind of the solvent and the sulfur ion source had influence on the size of silver sulfide nanoparticles. An interesting phenomenon was found in the TEM image of sampleⅡ: several long rods existed in the product and a tubular structure could be seen in one of these rods. The formation of this kind of special structure could be relevant to the coordination between thiourea and silver in water system.
文摘In recent years much attention has been devoted to AgCl emulsion owing to its se-rial advantages and inimitable potential. But in the research of this emulsion a thorny problem remains unsolved till now, which is the improvement in sensitivity is always accompanied with high fog density. In this work 5 nm Ag2S particles were prepared and used as novel sensitizers in AgCl cubic and {100} tabular microcrystal emulsions. The novel sensitizer shows an effective sensitizing ability for silver chloride emulsion, and it is superior to the traditional Na2S2O3 sensi-tizer because by using it comparatively high sensitivity can be obtained with lower fog density. So the above sensitizing problem is going to be effectively solved. To discover the evolution mechanism of the sensitizer clusters and explain their excellent sensitizing properties, diffuse reflectance spectroscopy (DRS) was used as a probe on the AgCl microcrystal surface.
基金supported by the Department of Science & Technology, New Delhi under SERC Scheme, DST No. SR/S1/PC-40/2006
文摘Porous Ag2S sensitized TiO2 catalysts were synthesized by the hydrothermal process.The crystallization and porous structure of the Ag2S/TiO2 composite photocatalysts were investigated by X-ray diffraction,scanning electron microscopy with energy dispersive X-ray analysis,UV-Vis diffuse reflectance spectroscopy,and N2 adsorption.The Ag2S/TiO2 composites were mainly composed of anatase TiO2 and acanthite Ag2S.The absorption edge wavelengths of TiO2 and the Ag2S/TiO2 composite prepared with 3 mmol Na2S.5H2O were 400 and 800 nm,respectively,that is,the absorption edge of the composite had a pronounced red shift.The photocatalytic activity under visible light was investigated by the degradation of methylene blue with a UV-Vis spectrophotometer.The photocatalytic activities under visible light of the Ag2S/TiO2 photocatalysts were much higher than that of TiO2.
