Oxygen Vacancy-Induced Novel Low-Temperature Water Splitting Reactions on FeO(111) Monolayer-Thick Film

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• 作者：Lingshun Xu ; Zongfang Wu ; Wenhua Zhang ; Yuekang Jin ; Qing Yuan ; Yunsheng Ma ; Weixin Huang
• 刊名：The Journal of Physical Chemistry C
• 出版年：2012
• 出版时间：November 1, 2012
• 年：2012
• 卷：116
• 期：43
• 页码：22921-22929
• 全文大小：538K
• 年卷期：v.116,no.43(November 1, 2012)
• ISSN：1932-7455

文摘

We have used XPS, UPS, and TDS to comparatively study water chemisorption and reaction on stoichiometric FeO(111) monolayer-thick film on Pt(111), stoichiometric FeO(111) monolayer-thick islands on Pt(111), and FeO(111) monolayer-thick films with oxygen vacancies on Pt(111) at 110 K. On stoichiometric FeO(111) monolayer-thick film, water undergoes reversible molecular adsorption. On stoichiometric FeO(111) monolayer-thick islands on Pt(111), water dissociates at coordination-unsaturated Fe(II) sites of the FeO(111)鈥揚t(111) interface to form OH following H₂O + Fe_CUS + FeO 鈫?Fe_CUS鈥揙_wH + FeOH in which O_w means O from H₂O. Upon heating, H₂ evolution occurs above 500 K. On FeO(111) monolayer-thick films with oxygen vacancies, water dissociates and molecularly chemisorbs to form a mixed adsorbate layer of H(a), OH, and H₂O(a) following both H₂O + Fe鈥揙_vacancy + FeO 鈫?FeO_wH + FeOH and H₂O + 2 Fe鈥揙_vacancy 鈫?FeO_wH + H(a)鈥揊e鈥揙_vacancy. Upon heating, besides the high-temperature H₂ evolution, additional H₂ desorption peaks appear simultaneously with the low-temperature desorption features of adsorbed H₂O(a), revealing novel low-temperature water splitting reactions. The formation of hydrated-proton surface species within a mixed adsorbate layer of H(a), OH, and H₂O(a) on FeO(111) monolayer-thick films with oxygen vacancies is proposed to explain such novel low-temperature water splitting reactions. These results greatly enrich the surface chemistry of water on solid surfaces.