Light Makes a Surface Banana-Bond Split: Photodesorption of Molecular Hydrogen from RuO2(110)

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• 作者：Michael A. Henderson ; Rentao Mu ; Arjun Dahal ; Igor Lyubinetsky ; Zdenek Dohnálek ; Vassiliki-Alexandra Glezakou ; Roger Rousseau
• 刊名：Journal of the American Chemical Society
• 出版年：2016
• 出版时间：July 20, 2016
• 年：2016
• 卷：138
• 期：28
• 页码：8714-8717
• 全文大小：327K
• 年卷期：0
• ISSN：1520-5126

文摘

The coordination of H₂ to a metal center via polarization of its σ bond electron density, known as a Kubas complex, is the means by which H₂ chemisorbs at Ru⁴⁺ sites on the rutile RuO₂(110) surface. This distortion of electron density off an interatomic axis is often described as a ‘banana-bond.’ We show that the Ru–H₂ banana-bond can be destabilized and split using visible light. Photodesorption of H₂ (or D₂) is evident by mass spectrometry and scanning tunneling microscopy. From time-dependent density functional theory, the key optical excitation splitting the Ru–H₂ complex involves an interband transition in RuO₂ which effectively diminishes its Lewis acidity, thereby weakening the Kubas complex. Such excitations are not expected to affect adsorbates on RuO₂ given its metallic properties. Therefore, this common thermal cocatalyst employed in photocatalysis is, itself, photoactive.