Strong Temperature Dependence in the Reactivity of H2 on RuO2(110)

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• 作者：Michael A. Henderson ; Arjun Dahal ; Zdenek Dohnálek ; Igor Lyubinetsky
• 刊名：The Journal of Physical Chemistry Letters
• 出版年：2016
• 出版时间：August 4, 2016
• 年：2016
• 卷：7
• 期：15
• 页码：2967-2970
• 全文大小：346K
• 年卷期：0
• ISSN：1948-7185

文摘

Understanding the reactivity of H₂ is of critical importance in controlling and optimizing many heterogeneous catalytic processes, particularly in cases where its adsorption on the catalyst surface is rate-limiting. In this work, we examine the temperature-dependent adsorption of H₂/D₂ on the clean RuO₂(110) surface using the King and Wells molecular beam approach, temperature-programmed desorption (TPD), and scanning tunneling microscopy (STM). We show that the adsorption probability of H₂/D₂ on this surface is highly temperature-dependent, decreasing from ∼0.4 below 25 K to <0.01 at 300 K. Both STM and TPD reveal that adsorption (molecular or dissociative) is severely limited once the temperature exceeds the trailing edge temperature of the H₂ TPD state (∼150 K). The presence of coadsorbed water or oxygen does not appear to alter this situation. Previous literature reports of extensive RuO₂(110) surface hydroxylation from H₂/D₂ exposures at 300 K may instead be the result of background contamination brought about by chamber backfilling.