Platinum/cerium-zirconium-sulfate（Pt/Ce-Zr-SO_4^（2-）） catalysts were prepared by wetness impregnation.Catalytic activities were evaluated from the combustion of propene and CO.Sulfate（SO_4^（2-））addition improv...Platinum/cerium-zirconium-sulfate（Pt/Ce-Zr-SO_4^（2-）） catalysts were prepared by wetness impregnation.Catalytic activities were evaluated from the combustion of propene and CO.Sulfate（SO_4^（2-））addition improved the catalytic activity significantly.When using Pt/Ce-Zr-SO_4^（2-） with 10 wt%SO_4^（2-）,the temperature for 90%conversion of propene and CO decreased by 75℃ compared with Pt/Ce-Zr.The conversion exceeded 95%at 240℃ even after 0.02%sulfur dioxide poisoning for 20 h.Temperature-programmed desorption of CO and X-ray photoelectron spectroscopy analyses revealed an improvement in Pt dispersion onto the Ce-Zr-SO_4^（2-） support,and the increased number of Pt particles built up more Pt^（-）-（SO_4^（2-））^（-） couples,which resulted in excellent activity.The increased total acidity and new Bronsted acid sites on the surface provided the Pt/Ce-Zr-SO_4^（2-） with good sulfur resistance.展开更多
Polyacrylamide （PAM） film was electrosynthesized on mild steel by cyclic voltammetry using Ce （IV） salt-oxalic acid as supporting electrolyte. Polymerization was initiated by a free radical that was formed by the ...Polyacrylamide （PAM） film was electrosynthesized on mild steel by cyclic voltammetry using Ce （IV） salt-oxalic acid as supporting electrolyte. Polymerization was initiated by a free radical that was formed by the fast reaction of oxalic acid and Ce （IV）. The electrolysis of the reaction solution resulted in regeneration of Ce （IV）, which could oxidize oxalic acid to produce radicals. The effect of temperature on the yield of electroinitiated polymerization was performed. The potential sweep rates were changed to achieve the polymer film with different thickness. Protective properties of the PAM film for corrosion of mild steel in 1 M NaCI aqueous solution were investigated by potentiodynamic polarization curves and electrochemical impedance spectroscopy （EIS）. The structure of PAM film on mild steel was investigated by using physicochemical methods such as elemental analysis of C, H, N, physical chemical methods and FTIR spectrometer. The influence of scan repetition and scan rate on the formation of polymer film was studied at a current density of 1 mA/cm2. The results of these studies reveal that the corrosion resistance of the PAM-coated mild steel was significantly higher and the corrosion rate was considerably lower than that of uncoated steel. The PAM film was formed with lower sweep rate leading to more positive shift of corrosion potential and greater charge transfer resistance, reflecting higher inhibition for corrosion of the mild steel.展开更多
基金supported by the National Natural Science Foundation of China(21506194,21676255)the Provincial Natural Science Foundation of Zhejiang Province(LY16B070011)the Commission of Science and Technology of Zhejiang Province(2017C33106,2017C03007)~~
文摘Platinum/cerium-zirconium-sulfate（Pt/Ce-Zr-SO_4^（2-）） catalysts were prepared by wetness impregnation.Catalytic activities were evaluated from the combustion of propene and CO.Sulfate（SO_4^（2-））addition improved the catalytic activity significantly.When using Pt/Ce-Zr-SO_4^（2-） with 10 wt%SO_4^（2-）,the temperature for 90%conversion of propene and CO decreased by 75℃ compared with Pt/Ce-Zr.The conversion exceeded 95%at 240℃ even after 0.02%sulfur dioxide poisoning for 20 h.Temperature-programmed desorption of CO and X-ray photoelectron spectroscopy analyses revealed an improvement in Pt dispersion onto the Ce-Zr-SO_4^（2-） support,and the increased number of Pt particles built up more Pt^（-）-（SO_4^（2-））^（-） couples,which resulted in excellent activity.The increased total acidity and new Bronsted acid sites on the surface provided the Pt/Ce-Zr-SO_4^（2-） with good sulfur resistance.
文摘Polyacrylamide （PAM） film was electrosynthesized on mild steel by cyclic voltammetry using Ce （IV） salt-oxalic acid as supporting electrolyte. Polymerization was initiated by a free radical that was formed by the fast reaction of oxalic acid and Ce （IV）. The electrolysis of the reaction solution resulted in regeneration of Ce （IV）, which could oxidize oxalic acid to produce radicals. The effect of temperature on the yield of electroinitiated polymerization was performed. The potential sweep rates were changed to achieve the polymer film with different thickness. Protective properties of the PAM film for corrosion of mild steel in 1 M NaCI aqueous solution were investigated by potentiodynamic polarization curves and electrochemical impedance spectroscopy （EIS）. The structure of PAM film on mild steel was investigated by using physicochemical methods such as elemental analysis of C, H, N, physical chemical methods and FTIR spectrometer. The influence of scan repetition and scan rate on the formation of polymer film was studied at a current density of 1 mA/cm2. The results of these studies reveal that the corrosion resistance of the PAM-coated mild steel was significantly higher and the corrosion rate was considerably lower than that of uncoated steel. The PAM film was formed with lower sweep rate leading to more positive shift of corrosion potential and greater charge transfer resistance, reflecting higher inhibition for corrosion of the mild steel.
