Oad在吸附于Ir(110)上的NH3分解中的作用：程序升温脱附与高能量分辨率快速X射线光电子能谱联用研究

The role of Oad in the decomposition of NH3 adsorbed on Ir(110): a combined TPD and high-energy resolution fast XPS study.

作者信息

Weststrate C J, Bakker J W, Rienks E D L, Vinod C P, Lizzit S, Petaccia L, Baraldi A, Nieuwenhuys B E

机构信息

Leids instituut voor chemisch onderzoek, Universiteit Leiden, P.O. Box 9502, Einsteinweg 55, 2300 RA Leiden, The Netherlands.

出版信息

Phys Chem Chem Phys. 2005 Jul 7;7(13):2629-34. doi: 10.1039/b502350e. Epub 2005 May 26.

DOI:10.1039/b502350e

PMID:16189574

Abstract

High energy resolution fast XPS combined with TPD experiments were used to study the effect of chemisorbed oxygen on the adsorption and dissociation of NH(3) on Ir(110). Below 250 K the presence of O(ad) does not influence NH(3) decomposition. Above 250 K O(ad) enhances NH(3) dissociation, which results in three times as much N(2) formation and less molecular NH(3) desorption compared to the experiments without O(ad). The effect of O(ad) can be attributed to destabilization of NH(ad) on the surface, resulting in a further dehydrogenation towards N(ad). The presence of O(ad) on the surface lowers the temperature at which the N(ad) combination reaction takes place by as much as 200 K, due to repulsive interaction between N(ad) and O(ad). NO is formed above 450 K if both N(ad) and O(ad) are present on the surface.

摘要

结合程序升温脱附（TPD）实验，利用高能量分辨率快速X射线光电子能谱（XPS）研究了化学吸附氧对NH₃在Ir(110)上吸附和解离的影响。在250 K以下，吸附氧（O(ad)）的存在不影响NH₃的分解。在250 K以上，O(ad)促进NH₃的解离，与不存在O(ad)的实验相比，这导致N₂生成量增加两倍，分子态NH₃脱附量减少。O(ad)的作用可归因于表面吸附态NH（NH(ad)）的稳定性降低，导致进一步脱氢生成吸附态氮（N(ad)）。由于N(ad)与O(ad)之间的排斥相互作用，表面存在O(ad)会使N(ad)化合反应发生的温度降低多达200 K。如果表面同时存在N(ad)和O(ad)，则在450 K以上会形成NO。