Atomic Hydrogen Activated TiO2 Nanocluster: DFT Calculations

详细信息    查看全文

• 作者：Alexey S. Andreev ; Vyacheslav N. Kuznetsov ; Yuri V. Chizhov
• 刊名：The Journal of Physical Chemistry C
• 出版年：2012
• 出版时间：August 30, 2012
• 年：2012
• 卷：116
• 期：34
• 页码：18139-18145
• 全文大小：274K
• 年卷期：v.116,no.34(August 30, 2012)
• ISSN：1932-7455

文摘

The reduction of TiO₂ nanoparticle through interaction with H atom and characterization of resulting defect species with O₂ molecule adsorption were investigated by DFT calculations in a molecular cluster approach. The isolated cluster Ti₈O₁₆ was used as a nanoparticle model. It was found that interaction between atomic hydrogen and every oxygen atom in Ti₈O₁₆ has the following features: (1) formation of stable OH group, (2) low activation energy of the process, and (3) appearance of reduced Ti³⁺ ion together with one corresponding d-type singly occupied level in the cluster鈥檚 鈥渂and gap鈥? Molecular hydrogen, in contrast with its atomic form, weakly interacts only with Ti atoms. Simulation of O₂ adsorption on each Ti³⁺ ion of reduced Ti₈O₁₆H clusters shows the following: (1) formation of stable molecular O₂^{鈥?/sup> species, (2) the process has no any energetic barrier, and (3) disappearance of Ti3+ defect center and corresponding d-type singly occupied level. The obtained results agree well with general experimental regularities of both H plasma TiO₂ reduction and interaction of reduced TiO₂ with oxygen. Specifically, calculations of g-tensor provide plausible quantitative description of Ti3+ and O₂鈥?/sup> paramagnetic species. Consistently the computational approach under consideration can be therefore applied to local surfaces phenomena associated with nanoscaled TiO₂.}