Hua D Y, Ma Y Q
National Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093, China.
Phys Rev E Stat Nonlin Soft Matter Phys. 2001 Nov;64(5 Pt 2):056102. doi: 10.1103/PhysRevE.64.056102. Epub 2001 Oct 17.
The irreversible kinetics of the Ziff-Gulari-Barshad model in the presence of inhomogeneity on a catalyst surface is investigated by means of Monte Carlo simulation. We assume that only part of catalyst surface sites are active for surface catalytic reaction and randomly distributed on the catalyst surface. The adsorption of a O2 molecule is permitted if one site of a nearest-neighbor vacant pair is active. CO can adsorb on all vacant sites, but the adsorption probability is p(p<1) if the site is not active. In our modified model, the O-passivated phase disappears and the continuous phase transition between the O passivated and the reactive state is eliminated. We also find that the transition between the CO passivated and the reactive state is continuous if the concentration of the active sites is small, and it becomes discontinuous with increasing concentrations of active sites. Furthermore, it is shown that a hysteresis loop exists whether the CO-passivated transition is continuous or discontinuous. Our simulation results are in good agreement with many relevant experimental results and may provide an alternative explanation for the experimental observations.
通过蒙特卡罗模拟研究了催化剂表面存在不均匀性时齐夫-古拉瑞-巴沙德模型的不可逆动力学。我们假设只有部分催化剂表面位点对表面催化反应具有活性，且这些位点随机分布在催化剂表面。如果最近邻空位对中的一个位点具有活性，则允许O₂分子吸附。CO可以吸附在所有空位上，但如果该位点没有活性，吸附概率为p（p<1）。在我们改进的模型中，O钝化相消失，O钝化态和反应态之间的连续相变被消除。我们还发现，如果活性位点的浓度较小，CO钝化态和反应态之间的转变是连续的，而随着活性位点浓度的增加，转变变得不连续。此外，结果表明，无论CO钝化转变是连续的还是不连续的，都存在滞后回线。我们的模拟结果与许多相关实验结果吻合良好，可能为实验观测提供另一种解释。
