催化作用
甲烷化
动力学蒙特卡罗方法
基本反应
蒙特卡罗方法
密度泛函理论
反应机理
化学
过渡状态
星团(航天器)
物理化学
水煤气变换反应
化学物理
计算化学
动力学
物理
生物化学
计算机科学
程序设计语言
量子力学
数学
统计
作者
Pablo Lozano‐Reis,Pablo Gamallo,R. Sayós,Francesc Illas
标识
DOI:10.1021/acscatal.3c05336
摘要
A detailed multiscale study of the mechanism of CO2 hydrogenation on a well-defined Ni/CeO2 model catalyst is reported that couples periodic density functional theory (DFT) calculations with kinetic Monte Carlo (kMC) simulations. The study includes an analysis of the role of Eley–Rideal elementary steps for the water formation step, which are usually neglected on the overall picture of the mechanism, catalytic activity, and selectivity. The DFT calculations for the chosen model consisting of a Ni4 cluster supported on CeO2 (111) show large enough adsorption energies along with low energy barriers that suggest this catalyst to be a good option for high selective CO2 methanation. The kMC simulations results show a synergic effect between the two 3-fold hollow sites of the supported Ni4 cluster with some elementary reactions dominant in one site, while other reactions prefer the another, nearly equivalent site. This effect is even more evident for the simulations explicitly including Eley–Rideal steps. The kMC simulations reveal that CO is formed via the dissociative pathway of the reverse water–gas shift reaction, while methane is formed via a CO2 → CO → HCO → CH → CH2 → CH3 → CH4 mechanism. Overall, our results show the importance of including the Eley–Rideal reactions and point to small Ni clusters supported on the CeO2 (111) surface as potential good catalysts for high selective CO2 methanation under mild conditions, while very active and selective toward CO formation at higher temperatures.
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