A highly ordered porous alumina template with pores of 45 nm in diameter was synthesized by a two-step electrochemical anodizing process. The influence of pore-enlargement treatment on the porous structure and tribolo...A highly ordered porous alumina template with pores of 45 nm in diameter was synthesized by a two-step electrochemical anodizing process. The influence of pore-enlargement treatment on the porous structure and tribological properties of the film was investigated, and ultrasonic impregnation technology was applied on it to form self-lubricating surface. The structure of the self-lubricating film and its tribological properties were investigated in detail. It can be concluded that the optimum time of pore-enlargement treatment is 20 min. The diameter of the pores and the surface porosity of the film are about 70 nm and 30%, respectively, while the film maintains the property of its high hardness. Under the same friction condition, the frictional coefficient of the self-lubricating film is 0. 18, much lower than that of the anodic aluminum oxide template, which is 0.52. In comparison with the lubricating surface of non-porous dense anodic aluminum oxide template, the lubricating surface fabricated by the ultrasonic impregnation method on the porous anodic aluminum oxide template keeps longer period with low friction coefficient. SEM examination shows that some C60 particles have been embedded in ultrasonic impregnation technology. the nanoholes of the anodic aluminum oxide template by the展开更多
The influence of the various preparation methods of Cu-SAPO-34 nanocatalysts on the selective catalytic reduction of NO with NH3 under excess oxygen was studied. Cu-SAPO-34 nanocatalysts were prepared by using four te...The influence of the various preparation methods of Cu-SAPO-34 nanocatalysts on the selective catalytic reduction of NO with NH3 under excess oxygen was studied. Cu-SAPO-34 nanocatalysts were prepared by using four techniques： conventional impregnation（IM）,ultrasound-enhanced impregnation（UIM）, conventional deposition precipitation（DP） using Na OH and homogeneous deposition precipitation（HDP） using urea. These catalysts were characterized in detail by various techniques such as N2-sorption, XRD, TEM, H2-TPR,NH3-TPD and XPS to understand the catalyst structure, the nature and the dispersed state of the copper species, and the acid sites for NH3 adsorption. All of the nanocatalysts showed high activities for NO removal. However, the activities were different and followed the sequence of Cu-SAPO-34（UIM） 〉 Cu-SAPO-34（HDP） 〉 Cu-SAPO-34（IM） 〉 Cu-SAPO-34（DP）.Based on the obtained results, it was concluded that the NO conversion on Cu-SAPO-34 nanocatalysts was mainly related to the high reducibility of the isolated Cu^2＋ions and Cu O species, the number of the acid sites and the dispersion of Cu O species on SAPO-34.展开更多
基金Project(2007CB607605) supported by the National Basic Research Program of China
文摘A highly ordered porous alumina template with pores of 45 nm in diameter was synthesized by a two-step electrochemical anodizing process. The influence of pore-enlargement treatment on the porous structure and tribological properties of the film was investigated, and ultrasonic impregnation technology was applied on it to form self-lubricating surface. The structure of the self-lubricating film and its tribological properties were investigated in detail. It can be concluded that the optimum time of pore-enlargement treatment is 20 min. The diameter of the pores and the surface porosity of the film are about 70 nm and 30%, respectively, while the film maintains the property of its high hardness. Under the same friction condition, the frictional coefficient of the self-lubricating film is 0. 18, much lower than that of the anodic aluminum oxide template, which is 0.52. In comparison with the lubricating surface of non-porous dense anodic aluminum oxide template, the lubricating surface fabricated by the ultrasonic impregnation method on the porous anodic aluminum oxide template keeps longer period with low friction coefficient. SEM examination shows that some C60 particles have been embedded in ultrasonic impregnation technology. the nanoholes of the anodic aluminum oxide template by the
基金financial support from University of Tabriz and Iranian Nanotechnology Initiative
文摘The influence of the various preparation methods of Cu-SAPO-34 nanocatalysts on the selective catalytic reduction of NO with NH3 under excess oxygen was studied. Cu-SAPO-34 nanocatalysts were prepared by using four techniques： conventional impregnation（IM）,ultrasound-enhanced impregnation（UIM）, conventional deposition precipitation（DP） using Na OH and homogeneous deposition precipitation（HDP） using urea. These catalysts were characterized in detail by various techniques such as N2-sorption, XRD, TEM, H2-TPR,NH3-TPD and XPS to understand the catalyst structure, the nature and the dispersed state of the copper species, and the acid sites for NH3 adsorption. All of the nanocatalysts showed high activities for NO removal. However, the activities were different and followed the sequence of Cu-SAPO-34（UIM） 〉 Cu-SAPO-34（HDP） 〉 Cu-SAPO-34（IM） 〉 Cu-SAPO-34（DP）.Based on the obtained results, it was concluded that the NO conversion on Cu-SAPO-34 nanocatalysts was mainly related to the high reducibility of the isolated Cu^2＋ions and Cu O species, the number of the acid sites and the dispersion of Cu O species on SAPO-34.
