Oxygen Atom Exchange between Gaseous CO2 and TiO2 Nanoclusters

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• 作者：Svatopluk Civi拧 ; Martin Ferus ; Mark茅ta Zukalov谩 ; Arno拧t Zukal ; Ladislav Kavan ; Kenneth D. Jordan ; Dan C. Sorescu
• 刊名：Journal of Physical Chemistry C
• 出版年：2015
• 出版时间：February 19, 2015
• 年：2015
• 卷：119
• 期：7
• 页码：3605-3612
• 全文大小：360K
• ISSN：1932-7455

文摘

Isotopic exchange of oxygen atoms between gaseous C¹⁸O₂ and Ti¹⁶O₂ nanoparticles has been studied using high-resolution Fourier transform infrared absorption and first-principles density functional theory calculations. The rate of formation of gaseous C¹⁶O₂ is found to be highly dependent on the nature of the titania sample, growing with increasing calcination temperature (i.e., with decreasing surface area) for both quasi-amorphous and crystalline samples. The unprecedented faster kinetics on high-surface-area titania made from Ti(IV) isopropoxide points at fundamental differences between this material and the usual nanocrystalline TiO₂ (anatase). This is attributed to unique cluster-like structure of the noncalcined ex-isopropoxide titania. The experimental observations are rationalized by calculations of the activation barriers for oxygen exchange on a (TiO₂)₁₀ cluster. The calculations predict that titanium nanoclusters with 4-fold coordinated titanium atoms have much lower barriers for O atom exchange than previously found for the oxygen defect sites on the single crystal (101) anatase surface.