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题名: The mechanism of H-2 and H2O desorption from bridging hydroxyls of a TiO2(110) surface
作者: Wang, Ruimin1, 2;  Fan, Hongjun1, 2
刊名: CATALYSIS SCIENCE & TECHNOLOGY
发表日期: 2017
DOI: 10.1039/c6cy02007k
卷: 7, 期:1, 页:251-264
收录类别: SCI
文章类型: Article
WOS标题词: Science & Technology ;  Physical Sciences
类目[WOS]: Chemistry, Physical
研究领域[WOS]: Chemistry
英文摘要: The photocatalytic H-2 production from H2O over TiO2 has attracted tremendous attention in recent years, and great progress has been achieved in light adsorption and water dissociation. As a comparison, the H-2 and O-2 production over a pure TiO2 surface has not been successful yet. Recently, the desorption of bridging hydroxyls (BBOHs) to form H-2 has been found to be possible on a TiO2(110) surface. However, the yield of H-2 is low, and the majority of BBOHs desorb as H2O. Here, for the first time, we have systematically studied the mechanism of H-2 desorption and the competition of H-2 and H2O desorption on a TiO2(110) surface with DFT methods. We found that the generally believed pathway, the direct coupling of BBOHs, is not the most facile pathway. We propose that the reaction undergoes a Ti-H key intermediate, which then forms an O-H delta+center dot center dot center dot H delta--Ti type dehydrogenation transition state. On a stoichiometric surface, the barriers for H-2 desorption and H2O desorption are 2.20 eV and 1.09 eV, respectively. However, with an increase in BBO vacancies (Ovs, created by H2O desorption), the barrier for H-2 desorption decreases, while the barrier for H2O desorption increases. Specifically, H-2 desorption was found to be easier than H2O desorption with our two Ovs TiO2 model. Therefore, our results predict that H2O desorption is dominant at the beginning, then H-2 desorption becomes more and more competitive. This prediction perfectly fits with the experimental observations. Furthermore, the stability of the key Ti-H intermediates and the possible ways for changing the conditions of H-2 desorption have also been discussed.
关键词[WOS]: MOLECULAR-HYDROGEN FORMATION ;  MINIMUM ENERGY PATHS ;  ELASTIC BAND METHOD ;  RUTILE TIO2(110) ;  AB-INITIO ;  TIO2 PHOTOCATALYSIS ;  SADDLE-POINTS ;  ADSORPTION ;  METHANOL ;  WATER
语种: 英语
WOS记录号: WOS:000392399900023
Citation statistics: 
内容类型: 期刊论文
URI标识: http://cas-ir.dicp.ac.cn/handle/321008/151863
Appears in Collections:中国科学院大连化学物理研究所_期刊论文

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作者单位: 1.Chinese Acad Sci, Dalian Inst Chem Phys, State Key Lab Mol React Dynam, 457 Zhongshan Rd, Dalian 116023, Liaoning Provin, Peoples R China
2.Univ Chinese Acad Sci, 19 A Yuquan Rd, Beijing 100049, Peoples R China

Recommended Citation:
Wang, Ruimin,Fan, Hongjun. The mechanism of H-2 and H2O desorption from bridging hydroxyls of a TiO2(110) surface[J]. CATALYSIS SCIENCE & TECHNOLOGY,2017,7(1):251-264.
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