The Adsorption Behaviors over Au Foil and The NO Reduction Behaviors over Au/TiO2 Catalyst

• Main Authors: Su, Yen-Shuo, 蘇彥碩
• Other Authors: Shawn D. Lin
• Format: Others
• Language: zh-TW
• Online Access: http://ndltd.ncl.edu.tw/handle/29147904215080851971

碩士 === 元智工學院 === 化學工程學系 === 84 === The adsorption of oxygen, carbon monoxide, nitrous oxide and nitric oxide overgold foil were studied by temperature programmed desorption (TPD) under ultra vacuum (UHV) environment. The uptaje of oxygen and carbon monoxide on the goldfoil surface at 323K were lower than the detecting limit of the instrument we used. Although the gold surface contains cobalt, rhodium and titanium or theiroxide was not significantly enhanced. Nitrous oxide could be adsorbed on gold foil only at very high dosing (360L) condition, and this is considered as an activated adsorption process. As to the nitric oxide adsorption study, there was one first-order desorption peakof nitric oxide from gold foil surface between 270K and 500K. The desorption activation energy, Ed, is approxmately 22kcal/mole when analyzed by Redhead method. The kinetic study of nitric oxide reduction by carbon monoxide showed that thepretreatment condition can significantly afect the catalytic activity of Au/ TiO2 catalyst. Among the different pretreatment conditions tested, The high temperature reduction/ calcination/ low temperature reduction (HTR/C/LTR) pretreatment procedure was found to provide the hightest activity, which is 3 times higher than those pretreated with only HTR or HTR/C, and is an order higher than those pretreated with only C or LTR procedure. The main reaction products were nitrous oxide and carbon dioxide at lower temperature range ( 323~423K) but nitrogen and carbon dioxide were found to occure at higher temperature. The catalytic activity of Au/TiO2(HTR/C/LTR) depended on temperature, and had a minimum at 523K; an Arrhenius dependency was followed for temperature higher than 523K, but a slow decreasing was observed form 323 to 523K