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首页> 外文期刊>Physical review. B, Condensed Matter And Materals Physics >NO oxidation properties of Pt(111) revealed by ab initio kinetic simulations
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NO oxidation properties of Pt(111) revealed by ab initio kinetic simulations

机译：从头算动力学模拟揭示Pt（111）的NO氧化性能

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As a well-known oxidation catalyst, platinum is currently being used to convert NO to NO_2 for absorption in so-called NO_x traps under excess oxygen conditions, where direct conversion of NO to nitrogen gas is prohibitive. By performing kinetic Monte Carlo simulations with parameters derived from density-functional theory, we show that this oxidation process is not an inherent property of the platinum catalyst itself. In fact, the intrinsic NO+O → NO_2 reaction is found to be inhibited (endothermic) rather than promoted on Pt(111), due to strong oxygen-platinum bonds. Only at sufficient oxygen chemical potential does platinum become an efficient oxidation catalyst, as its oxygen bonds are weakened with increasing coverage, and the NO_2 formation reaction becomes exothermic. At that point, Pt catalyzes the reaction by lowering the activation barrier for the kinetic reaction. Congruent with flow-reactor experiments, we note a strong temperature dependence for the turnover frequency, which should encourage further ultra-high vacuum studies.
机译：作为公知的氧化催化剂，铂目前被用于在过量的氧气条件下将NO转化为NO_2以在所谓的NO_x阱中吸收，在该条件下，将NO直接转化为氮气是禁止的。通过用从密度泛函理论推导的参数进行动力学蒙特卡洛模拟，我们表明该氧化过程不是铂催化剂本身的固有性质。实际上，由于强的氧-铂键，固有的NO + O→NO_2反应被抑制（吸热），而不是在Pt（111）上被促进。铂只有在足够的氧化学势下才能成为有效的氧化催化剂，因为其氧键会随着覆盖率的增加而减弱，并且NO_2的形成反应会放热。那时，Pt通过降低动力学反应的活化障碍来催化反应。与流动反应器实验一致，我们注意到周转频率对温度有很强的依赖性，这应该鼓励进一步的超高真空研究。

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