arXivDaily arXiv每日学术速递 周一至周五更新
arXiv physics/0409153physics.chem-ph
收藏

负载型催化剂上的溢出-动态蒙特卡罗研究

Spillover on supported catalysts - Dynamic Monte Carlo study

Lukasz Cwiklik, Barbara Jagoda-Cwiklik, Marek Frankowicz

摘要:

用动态蒙特卡罗模拟研究了具有溢出效应的负载型金属催化剂上2A + B2 = 2AB反应的动力学。在所提出的模型中,A粒子可以可逆地吸附在金属簇和载体上,而B2粒子只能解离吸附在金属簇上。颗粒A可以从载体扩散到金属簇,反之亦然。该模型描述了CO在Pd/Al_2O_3催化剂上的氧化。稳态反应速率和表面覆盖率的研究作为在气相中的反应物的分压的函数。模拟结果表明,溢出效应通过增大反应速率和拓宽反应压力窗口而显著改变了反应速率。在具有溢出的系统中,除了溢出通道之外,还观察到由吸附通道驱动的反应。反应速率对反应物分压的依赖性可以通过改变溢流和吸附通道贡献来控制。

英文摘要:

The kinetics of a 2A + B2 = 2AB reaction on supported metal catalyst with spillover effects is investigated using Dynamic Monte Carlo simulations. In the presented model A particles can adsorb reversibly on both metal clusters and the support whereas B2 particles can adsorb dissociatively only on metal clusters. Particles A can diffuse from the support to metal clusters and vice versa. The model describes CO oxidation on Pd/Al2O3 catalyst. Steady-state reaction rates and surface coverages are investigated as functions of partial pressures of reactants in the gas phase. Simulations show that spillover effects change the reaction rate dramatically by increasing it and widening the pressure window of the reaction. In systems with spillover the reaction driven by an adsorption channel, in addition to a spillover channel, is observed. The character of the dependence of the reaction rate on reactants' partial pressures can be controlled by changes of spillover and adsorption channel contributions.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑