CO气体分子在金属氧化物SrO(001)表面吸附和脱附机理

Mechanism of Adsorption and Desorption of CO on SrO(001) Surface

研究了高纯度金属氧化物SrO粉末表面吸附C18O后在程序升温热脱附过程中的脱附反应规律 ,讨论了CO气体分子在SrO( 10 0 )表面吸附和脱附之间的关系及机理 .SrO吸附C18O后 ,在升温过程中可通过氧的同位素交换生成C16O而脱附 ,同时伴随少量C18O的直接脱附 ,并与C16O具有相近的脱附活化能 .C16O的脱附量随C18O气体暴露量增加而增加 ,但当气体覆盖度超过一定值后 ,脱附量趋于定值 .脱附峰值温度随气体暴露量的增加而下降 .

The desorption behaviors of (CO)-O-18 on the particle surface of SrO (001) were investigated by the method of Temperature Programmed Desorption (TPD). The mechanism responsible for desorption process and the relationship between adsorption and desorption were discussed. (CO)-O-16 formed due to the exchange of oxygen isotopes and escaped from the surface of SrO particles during heating the particles pretreated with the absorption of (CO)-O-18 gas. A small amount of (CO)-O-18 also desorbed from the particle surface and the activation energy of (CO)-O-18 desorption was approximate to that of (CO)-O-16 desorption. With the increasing of the exposure amount of (CO)-O-18 gas, the desorption amount of (CO)-O-16 was increased and the peak desorption temperature was decreased. However, the desorption amount of (CO)-O-16 tended to become constant when the surface coverage of (CO)-O-18 gas was higher than a certain value.