CO,O_2,H_2O预覆盖对钯吸氢速率的影响

Hydriding Rate of Palladium Powders Precovered with O_2,CO or H_2O

为了考察杂质气体对钯吸氢速率的影响,测定了钯粉末暴露在CO,O2,H2O中后25℃下的吸氢速率。与洁净钯吸氢速率相比,CO预覆盖引起钯吸氢速率降低最为显著,H2O次之;少量O2预覆盖却能引起钯吸氢速率显著增加。引起吸氢速率变化的微观机制主要是受氢原子在氢化物层的扩散或钯表面解离氢分子的化学吸附;O2预覆盖可使Pd表面形成多孔结构而增加了氢分子的解离位,从而增加吸氢速率;CO预覆盖后却占领了钯表面的氢分子解离位而减小了吸氢速率。250℃下的O2预处理是CO毒化钯活化的有效方法。

To study the effect on the hydriding properties of contamination gases palladium, Pd powder samples were exposed to contamination gases such as CO, O2 as well as H2O. H2 absorbing rates of the sampies were measured at 25℃. The hydriding rate decreases drastically when samples precover with CO, H2O comparing with that of clean Pd, whereas the reaction rate increases sharply for little O2 precovered samples. The controlled processes of the rate on hydriding are chemisorptions or diffusion. The pore structure of Pd precovered with O2 increase the number of the sites for hydrogen dissociation, thus leads hydriding rate increases sharply. Whereas samples precovered with CO cause the sites blocking leaded hydriding rate to decrease. Regeneration of CO poisoned palladium samples using O2 at 250℃ is an effective way.