Photoinduced Decomposition of Formaldehyde on a TiO2(110) Surface, Assisted by Bridge-Bonded Oxygen Atoms
Photoinduced Decomposition of Formaldehyde on a TiO2(110) Surface, Assisted by Bridge-Bonded Oxygen Atoms
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DOI：
10.1021/jz401349q
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发表时间：
2013-07
影响因子：
5.7
通讯作者：
Chenbiao Xu;Wenshao Yang;Qing Guo;D. Dai;T. Minton;Xueming Yang
中科院分区：
文献类型：
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作者：
Chenbiao Xu;Wenshao Yang;Qing Guo;D. Dai;T. Minton;Xueming Yang
我们利用程序升温脱附技术研究了在400nm波长下甲醛（CH₂O）在TiO₂(110)表面的光诱导分解。检测到了甲酸根（HCOO）、甲基自由基（CH₃）和乙烯（C₂H₄），但没有发现甲醛聚合的证据。甲醛在TiO₂(110)表面分解的起始步骤是形成二氧亚甲基中间体，其中甲醛的羰基氧原子既与五配位晶格位点（Ti₅C）上的一个钛原子结合，又与附近的桥连氧（BBO）原子结合。在400nm光照期间，二氧亚甲基中间体可将亚甲基转移至桥连氧排并断裂C - O键，从而使原始的羰基氧原子留在Ti₅C位点。在亚甲基转移之后，有几种生成产物的途径。因此我们发现，桥连氧原子密切参与了甲醛在TiO₂(110)表面的光诱导分解。
We have investigated the photoinduced decomposition of formaldehyde (CH2O) on TiO2(110) at 400 nm using temperature-programmed desorption. Formate (HCOO), methyl radicals (CH3), and ethylene (C2H4) have been detected, while no evidence of polymerization of CH2O was found. The initial step in the decomposition of CH2O on TiO2(110) is the formation of a dioxymethylene intermediate in which the carbonyl O atom of CH2O is bound both to a Ti atom on the five-fold-coordinated lattice site (Ti5C) and to a nearby bridge-bonded oxygen (BBO) atom. During 400 nm irradiation, the dioxymethylene intermediate can transfer methylene to the bridging oxygen row and break the C–O bond, thus leaving the original carbonyl O atom on the Ti5C site. After this transfer of methylene, several pathways to products are available. Thus we have found that BBO atoms are intimately involved in the photoinduced decomposition of CH2O on TiO2(110).