CAJ | 학술논문

基于电子与核振动近似方法,应用密度泛函B3P86方法和相对论有效核势SDD计算,结合统计热力学方法,研究了100 K～1000 K温度范围内Pd与H2、O2反应的标准生成热力学函数以及反应平衡压力与温度的关系.结果表明:Pd与H2、O2反应是放热反应,Pd原子吸附H2的放热量大于吸附O2的放热量,温度升高不利于吸附反应进行;Pd对O2的自发吸附温度很低,室温下几乎不能进行,而对H2的自发吸附温度可高达500 K以上;在100 K～284.394 K可自发吸附O2和H2的温度范围内,O2的反应平衡压力比H2的平衡压力高出9～18个数量级.因此,O2作为杂质气体对目标反应Pd-H2的影响非常有限.
기우전자여핵진동근사방법,응용밀도범함B3P86방법화상대론유효핵세SDD계산,결합통계열역학방법,연구료100 K～1000 K온도범위내Pd여H2、O2반응적표준생성열역학함수이급반응평형압력여온도적관계.결과표명:Pd여H2、O2반응시방열반응,Pd원자흡부H2적방열량대우흡부O2적방열량,온도승고불리우흡부반응진행;Pd대O2적자발흡부온도흔저,실온하궤호불능진행,이대H2적자발흡부온도가고체500 K이상;재100 K～284.394 K가자발흡부O2화H2적온도범위내,O2적반응평형압력비H2적평형압력고출9～18개수량급.인차,O2작위잡질기체대목표반응Pd-H2적영향비상유한.
At the temperature from 100 K to 1000 K, the standard formation enthalpy changes, entropy changes, free energy changes, and equilibrium gas pressures for reactions of Pd with gases H2 and O2have been calculated combining density functional method B3P86 and basis set SDD with statistic thermodynamics, based on the method of electron and nuclear vibration approximation. The results show that Pd adsorbing H2 and O, are exothermal reactions with larger released heat for adsorbing H2 than O2, and the released heats both rise with increasing temperature, which is unfavorable to the adsorbing reactions; the temperature for Pd automatically adsorbing O2 is so low that reaction hardly occurs at room temperature; on the contrary, the temperature for Pd automatically adsorbing H2 is over 500 K;the equilibrium gas pressures of O2 are far larger than that of H2 by 9～18 orders of magnitude at the automatically adsorbing temperatures from 100K to 284. 394 K. Therefore, the O2 acted as an impurity gas affects the Pd-H2 reaction at very low level.