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Investigation on the Transformation of Absorbed Oxygen at ZnO {101̅0} Surface Based on a Novel Thermal Pulse Method and Density Functional Theory Simulation
ACS Sensors ( IF 8.2 ) Pub Date : 2017-07-19 00:00:00 , DOI: 10.1021/acssensors.7b00363 Tingqiang Yang 1 , Yueli Liu 1 , Wei Jin 1 , Yiyang Han 1 , Shuang Yang 1 , Wen Chen 2
ACS Sensors ( IF 8.2 ) Pub Date : 2017-07-19 00:00:00 , DOI: 10.1021/acssensors.7b00363 Tingqiang Yang 1 , Yueli Liu 1 , Wei Jin 1 , Yiyang Han 1 , Shuang Yang 1 , Wen Chen 2
Affiliation
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Absorbed oxygen plays a key role in gas sensing process of ZnO nanomaterials. In this work, the transformation of absorbed oxygen on ZnO (101̅0) and its effects on gas sensing properties to ethanol are studied by a novel thermal pulse method and density functional theory (DFT) simulation. Thermal pulse results reveal that the absorbed O2 molecule dissociates into two individual oxygen adatoms by extracting electrons from ZnO surface layers when temperature is above 443 K. The temperature at which absorbed O2 molecule begins to dissociate is the lowest working temperature for gas sensing. DFT simulation demonstrates the dissociation process of O2 at ZnO (101̅0) surface, and the activation energy (Ea) of dissociation is calculated to be 351.71 kJ/mol, which suggests that the absorbed O2 molecule is not likely to dissociate at room temperature. The reactions between ethanol and absorbed O2 molecule, as well as reactions between ethanol and O adatom, are also simulated. The results indicate that ethanol cannot react with absorbed O2 molecule, while it can be oxidized by O adatom to acetaldehyde and then to acetic acid spontaneously. Mulliken charge analysis suggests electrons extracted by O adatom return to ZnO after the oxidation of ethanol.
中文翻译：
基于新型热脉冲方法和密度泛函理论模拟的ZnO {101̅0}表面吸收氧的转化研究
吸收的氧气在ZnO纳米材料的气敏过程中起着关键作用。在这项工作中，通过新颖的热脉冲方法和密度泛函理论（DFT）模拟研究了ZnO（101̅0）上吸收的氧的转化及其对气敏特性的影响，从而转化为乙醇。热脉冲结果表明，所吸收的ø 2由当温度高于443 K.在该吸收○温度由ZnO表面层引出电子分子离解成两个单独的氧吸附原子2分子开始解离为气体感测的最低工作温度。DFT模拟证明了O 2在ZnO（101̅0）表面的解离过程以及活化能（E a）的解离被计算为351.71kJ / mol，这表明被吸收的O 2分子在室温下不太可能解离。还模拟了乙醇与被吸收的O 2分子之间的反应，以及乙醇与O原子之间的反应。结果表明乙醇不能与吸收的O 2分子反应，而可以被O原子原子氧化为乙醛，然后自然氧化为乙酸。Mulliken电荷分析表明，O原子提取的电子在乙醇氧化后返回ZnO。
更新日期：2017-07-20
中文翻译：
基于新型热脉冲方法和密度泛函理论模拟的ZnO {101̅0}表面吸收氧的转化研究
吸收的氧气在ZnO纳米材料的气敏过程中起着关键作用。在这项工作中，通过新颖的热脉冲方法和密度泛函理论（DFT）模拟研究了ZnO（101̅0）上吸收的氧的转化及其对气敏特性的影响，从而转化为乙醇。热脉冲结果表明，所吸收的ø 2由当温度高于443 K.在该吸收○温度由ZnO表面层引出电子分子离解成两个单独的氧吸附原子2分子开始解离为气体感测的最低工作温度。DFT模拟证明了O 2在ZnO（101̅0）表面的解离过程以及活化能（E a）的解离被计算为351.71kJ / mol，这表明被吸收的O 2分子在室温下不太可能解离。还模拟了乙醇与被吸收的O 2分子之间的反应，以及乙醇与O原子之间的反应。结果表明乙醇不能与吸收的O 2分子反应，而可以被O原子原子氧化为乙醛，然后自然氧化为乙酸。Mulliken电荷分析表明，O原子提取的电子在乙醇氧化后返回ZnO。
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