A series of K-promoted Pt/Al2O3 catalysts were tested for CO oxidation. It was found that the addition of K significantly enhanced the activity. A detailed kinetic study showed that the activation energies of the K-co...A series of K-promoted Pt/Al2O3 catalysts were tested for CO oxidation. It was found that the addition of K significantly enhanced the activity. A detailed kinetic study showed that the activation energies of the K-containing catalysts were lower than those of the K-free ones, particularly for catalysts with high Pt contents （51.6 k）/mol for 0.42K-2.0Pt/Al2O3 and 6：3.6 kJ/mol for 2.0Pt/Al2O3 ）. The CO reaction orders were higher for the K-containing catalysts （about -0.2） than for the K-free ones （about -0.5）, with the former having much lower equilibrium constants for CO adsorption than the latter. In situ Fourier-transform infrared spectroscopy showed that surface CO desorption from the 0.42K-2.0Pt/Al2O3 catalyst was easier than from 2.0Pt/Al2O3. The promoting effect of K was therefore caused by weakening of the interactions between CO and surface Pt atoms. This decreased coverage of the catalyst with CO and facilitated competitive O2 chemisorption on the Pt surface, and significantly lowered the reaction barrier between chemisorbed CO and O2 species.展开更多
The dyeing behavior of cationic dyes to acrylic fiber with self-made low temperature dyeing accelerant was investigated in this study. Compared with conventional dyeing, the acrylic yarn was dyed with Cationic Turquoi...The dyeing behavior of cationic dyes to acrylic fiber with self-made low temperature dyeing accelerant was investigated in this study. Compared with conventional dyeing, the acrylic yarn was dyed with Cationic Turquoise Blue X-GB at 85℃ in the presence of accelerant and absence of accelerant, respectively. The influence of low temperature dyeing aceelerant on the dyeing mechanism of acrylic fiber dyed with cationic dye was analyzed through kinetics and thermodynamics study. The results show that adding dyeing accelerant ran heighten the equilibrium dye-uptake, dyeing rate constants, diffusion coefficients, and shorten half-dyeing time for acrylic fiber dyed with cationic dyes. Furthermore, the partition coefficient, the standard affinity, and the dye saturation value also increased in the dyeing at 85℃.展开更多
基金financially supported by the National Natural Science Foundation of China(21173195)~~
文摘A series of K-promoted Pt/Al2O3 catalysts were tested for CO oxidation. It was found that the addition of K significantly enhanced the activity. A detailed kinetic study showed that the activation energies of the K-containing catalysts were lower than those of the K-free ones, particularly for catalysts with high Pt contents （51.6 k）/mol for 0.42K-2.0Pt/Al2O3 and 6：3.6 kJ/mol for 2.0Pt/Al2O3 ）. The CO reaction orders were higher for the K-containing catalysts （about -0.2） than for the K-free ones （about -0.5）, with the former having much lower equilibrium constants for CO adsorption than the latter. In situ Fourier-transform infrared spectroscopy showed that surface CO desorption from the 0.42K-2.0Pt/Al2O3 catalyst was easier than from 2.0Pt/Al2O3. The promoting effect of K was therefore caused by weakening of the interactions between CO and surface Pt atoms. This decreased coverage of the catalyst with CO and facilitated competitive O2 chemisorption on the Pt surface, and significantly lowered the reaction barrier between chemisorbed CO and O2 species.
基金Science and Technology Department of Zhejiang Province,China (No. 2008C01069-4)
文摘The dyeing behavior of cationic dyes to acrylic fiber with self-made low temperature dyeing accelerant was investigated in this study. Compared with conventional dyeing, the acrylic yarn was dyed with Cationic Turquoise Blue X-GB at 85℃ in the presence of accelerant and absence of accelerant, respectively. The influence of low temperature dyeing aceelerant on the dyeing mechanism of acrylic fiber dyed with cationic dye was analyzed through kinetics and thermodynamics study. The results show that adding dyeing accelerant ran heighten the equilibrium dye-uptake, dyeing rate constants, diffusion coefficients, and shorten half-dyeing time for acrylic fiber dyed with cationic dyes. Furthermore, the partition coefficient, the standard affinity, and the dye saturation value also increased in the dyeing at 85℃.
