催化作用
化学
氧化钒
吸附
布朗斯特德-洛瑞酸碱理论
氧化物
路易斯酸
选择性催化还原
无机化学
钒
氧气
星团(航天器)
脱氢
密度泛函理论
氮氧化物
基质(水族馆)
物理化学
计算化学
有机化学
计算机科学
程序设计语言
海洋学
燃烧
地质学
作者
Mathis Gruber,Klaus Hermann
摘要
We consider different reaction scenarios of the selective catalytic reduction (SCR) of NO in the presence of ammonia at perfect as well as reduced vanadium oxide surfaces modeled by V2O5(010) without and with oxygen vacancies. Geometric and energetic details as well as reaction paths are evaluated using extended cluster models together with density-functional theory. Based on earlier work of adsorption, diffusion, and reaction of the different surface species participating in the SCR we confirm that at Brønsted acid sites (i.e., OH groups) of the perfect oxide surface nitrosamide, NH2NO, forms a stable intermediate. Here adsorption of NH3 results in NH4 surface species which reacts with gas phase NO to produce the intermediate. Nitrosamide is also found as intermediate of the SCR near Lewis acid sites of the reduced oxide surface (i.e., near oxygen vacancies). However, here the adsorbed NH3 species is dehydrogenated to surface NH2 before it reacts with gas phase NO to produce the intermediate. The calculations suggest that reaction barriers for the SCR are overall higher near Brønsted acid sites of the perfect surface compared with Lewis acid sites of the reduced surface, examined for the first time in this work. The theoretical results are consistent with experimental findings and confirm the importance of surface reduction for the SCR process.
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