CO在Pd平板与Pd38团簇表面上的催化氧化机理研究  

Catalytic oxidation of CO on Pd38 cluster and Pd slab, a computational study

作　　者：齐大彬[1] 罗旭东[1] 姚君 姚玉龙 芦晓军 QI Da-bin;LUO Xu-dong;YAO Jun;YAO Yu-long;LU Xiao-jun(Liaoning University of Science and Technology,Anshan 114000,China;Angang Iron and Steel Research Institute,Anshan 114000,China;Fushun Petrochemical Company of CNPC,Fushun 113000,China)

机构地区：[1]辽宁科技大学,辽宁鞍山114000 [2]鞍钢集团钢铁研究院,辽宁鞍山114000 [3]中石油抚顺石化公司,辽宁抚顺113000

出　　处：《燃料化学学报》2020年第4期432-439,I0004,共9页Journal of Fuel Chemistry and Technology

基　　金：国家自然科学基金(51772139)资助。

摘　　要：采用密度泛函理论(DFT)计算模拟Pd平板和Pd38团簇上的CO催化氧化过程,分析了CO在Pd催化剂表面上的氧化反应机理。结果表明,在Pd38团簇模型上CO催化氧化的决速步骤是O2的解离,反应能垒为0.65 eV,而在Pd平板模型上的决速步骤是CO的氧化,其反应能垒为0.87 eV。对比决速步骤的活化能发现,CO在Pd38团簇上的氧化反应更易进行,说明CO氧化更易在小颗粒催化剂表面上进行,即Pd催化剂的活性与活性组分颗粒大小相关,活性组分颗粒越小,暴露的活性位点越多,其催化活性也越高。The catalytic oxidation of CO was comparatively investigated on the Pd slab and Pd38 cluster models by density functional theory(DFT) calculation, in order to reveal the mechanism of CO oxidation over Pd catalysts. The results show that the rate-determining step of CO oxidation on the Pd38 cluster is the dissociation of O2, with the energy barrier of 0.65 eV, whereas the oxidation of CO turns to be the rate-determining step on Pd slab, with the energy barrier of 0.87 eV. Obviously, the oxidation of CO on the Pd38 cluster is much easier than that on the Pd slab, suggesting that the activity of Pd catalysts is related to the dispersion of active Pd species;the Pd catalyst with higher Pd dispersion also exhibits higher activity in CO oxidation.

关 键 词：密度泛函理论计算 CO催化氧化 Pd平板模型 Pd38团簇模型 

分 类 号：O643.32[理学—物理化学]