载钯硅藻土吸氕/氘动力学同位素效应

Hydrogen Isotopes Absorption Kinetics of Palladium/Kieselguhr

恒温等容条件下,通过p-t曲线测量,研究在223～393K范围内载钯硅藻土（Pd/K）吸氕、氘动力学特性。应用反应速率分析方法计算了反应速率常数,得到了Pd/K吸氕、氘反应活化能。动力学计算结果显示：在整个温度范围内,载钯硅藻土与氕、氘反应明显分为两个温度段。低温段（223～313K）,载钯硅藻土吸氕、氘反应速率常数随温度升高而增大且吸氕反应速率大于吸氘反应速率,吸氕、氘反应活化能分别为19.5、19.2kJ/mol;高温段（313～393K）,载钯硅藻土吸氕、氘反应速率则随温度升高而减小,氕、氘反应活化能分别为：-18.6、-12.1kJ/mol。测试结果表明,载钯硅藻土吸氕、氘反应存在显著的动力学同位素效应且同位素效应依赖于温度的变化。

The pressure-time curves of hydrogen reacting with Pd/K were investigated at223-393 K by using the method of the reaction rate analysis at constant temperature and volume.Dynamics analysis suggests that the adsorption reaction at the whole temperature range can be divided into two stages,the low temperature range（223-313 K）and the high temperature range（313-393K）.At the low temperature range,the rate constants increase with the temperature for protium and deuterium.The activity energy is 19.5 kJ/mol,19.2kJ/mol,respectively. However,the rate constants decline with the temperature increasing at the high temperature range,and the activity energy is-18.6kJ/mol,-12.1kJ/mol,respectively.The changing of activation energy shows remarkable kinetics isotope effects and the isotope effects depend on temperature.