基于量子化学密度泛函理论和过渡态理论研究了含酮基团对煤焦异相还原NO的影响及其产物发生氧脱附的微观反应机理。计算结果表明,NO更易于吸附在含酮基团煤焦表面。椅形含酮基团强化了煤焦异相还原NO;锯齿形含酮煤焦表面与NO异相反应决...基于量子化学密度泛函理论和过渡态理论研究了含酮基团对煤焦异相还原NO的影响及其产物发生氧脱附的微观反应机理。计算结果表明,NO更易于吸附在含酮基团煤焦表面。椅形含酮基团强化了煤焦异相还原NO;锯齿形含酮煤焦表面与NO异相反应决速步能垒值(495.45 k J/mol)大于锯齿形纯碳基煤焦表面与NO决速步能垒值(331.32 k J/mol),基于锯齿形含酮煤焦模型中的氧浓度不在利于NO还原的范围内而不易于NO的还原。中间产物P1在无CO存在情况下,较纯碳基煤焦表面更易于发生氧脱附而产生表面缺陷;在CO存在条件下,含酮煤焦表面为氧脱附过程提供自由活性位点,降低了过程能垒消耗。展开更多
Various Au/GO catalysts were prepared by depositing Au nanoparticles on thermally- and chemically-treated graphite oxide （GO） supports using a sol-immobilization method. The surface chemistry and structure of GO sup...Various Au/GO catalysts were prepared by depositing Au nanoparticles on thermally- and chemically-treated graphite oxide （GO） supports using a sol-immobilization method. The surface chemistry and structure of GO supports were characterized by a series of analytical techniques including X-ray photoelectron spectroscopy, temperature-programmed desorption and Raman spectroscopy. The results show that thermal and chemical treatments have large influence on the presence of surface oxygenated groups and the crystalline structure of GO supports. A strong support effect was observed on the catalytic activity of Au/GO catalysts in the liquid phase aerobic oxidation of benzyl alcohol. Compared to the amount and the type of surface oxygen functional groups, the ordered structure of GO supports may play a more important role in determining the catalytic performance of Au/GO catalysts.展开更多
The results of studying the interaction of H2 and O2 with Pt-, Ru- and Pt-Ru catalysts supported on 2% Ce/（θ＋α）-AlEO3, at varying the ratios and concentrations of supported elements by using the temperature-progr...The results of studying the interaction of H2 and O2 with Pt-, Ru- and Pt-Ru catalysts supported on 2% Ce/（θ＋α）-AlEO3, at varying the ratios and concentrations of supported elements by using the temperature-programmed desorption method are presented. It has been shown that HE is adsorbed as four forms, differing in the structure, temperature, order and activation energy of desorption： HEads, HE＋ads, Hads, Hat （Tdes 〉 873 K）. The relationship of activity and selectivity of Pt-Ru catalysts with the presence of active centers able to adsorb atomic hydrogen with desorption energy （Edes） = 60-70 kJ/mol in the catalytic oxidation of methane was determined. It was found that the O2 adsorbed as two forms differing in the structure, temperature and activation energy of desorption. It has been determined that changing the atomic ratio of elements in the catalysts significantly affect on the adsorption Of OE. The introduction of ruthenium into the platinum catalyst increases the oxygen adsorption; and the surface is stabilized in a homogeneous state. Quantum chemical calculations of the activation of C-H bonds in a molecule of methane on Ru,,Pt, （m ＋ n = 4） clusters have been carried out.展开更多
文摘基于量子化学密度泛函理论和过渡态理论研究了含酮基团对煤焦异相还原NO的影响及其产物发生氧脱附的微观反应机理。计算结果表明,NO更易于吸附在含酮基团煤焦表面。椅形含酮基团强化了煤焦异相还原NO;锯齿形含酮煤焦表面与NO异相反应决速步能垒值(495.45 k J/mol)大于锯齿形纯碳基煤焦表面与NO决速步能垒值(331.32 k J/mol),基于锯齿形含酮煤焦模型中的氧浓度不在利于NO还原的范围内而不易于NO的还原。中间产物P1在无CO存在情况下,较纯碳基煤焦表面更易于发生氧脱附而产生表面缺陷;在CO存在条件下,含酮煤焦表面为氧脱附过程提供自由活性位点,降低了过程能垒消耗。
基金This work was supported by the Natural Science Foundation of Anhui Province （No.11040606M39） and the Fundamental Research Funds for the Central Universities.
文摘Various Au/GO catalysts were prepared by depositing Au nanoparticles on thermally- and chemically-treated graphite oxide （GO） supports using a sol-immobilization method. The surface chemistry and structure of GO supports were characterized by a series of analytical techniques including X-ray photoelectron spectroscopy, temperature-programmed desorption and Raman spectroscopy. The results show that thermal and chemical treatments have large influence on the presence of surface oxygenated groups and the crystalline structure of GO supports. A strong support effect was observed on the catalytic activity of Au/GO catalysts in the liquid phase aerobic oxidation of benzyl alcohol. Compared to the amount and the type of surface oxygen functional groups, the ordered structure of GO supports may play a more important role in determining the catalytic performance of Au/GO catalysts.
文摘The results of studying the interaction of H2 and O2 with Pt-, Ru- and Pt-Ru catalysts supported on 2% Ce/（θ＋α）-AlEO3, at varying the ratios and concentrations of supported elements by using the temperature-programmed desorption method are presented. It has been shown that HE is adsorbed as four forms, differing in the structure, temperature, order and activation energy of desorption： HEads, HE＋ads, Hads, Hat （Tdes 〉 873 K）. The relationship of activity and selectivity of Pt-Ru catalysts with the presence of active centers able to adsorb atomic hydrogen with desorption energy （Edes） = 60-70 kJ/mol in the catalytic oxidation of methane was determined. It was found that the O2 adsorbed as two forms differing in the structure, temperature and activation energy of desorption. It has been determined that changing the atomic ratio of elements in the catalysts significantly affect on the adsorption Of OE. The introduction of ruthenium into the platinum catalyst increases the oxygen adsorption; and the surface is stabilized in a homogeneous state. Quantum chemical calculations of the activation of C-H bonds in a molecule of methane on Ru,,Pt, （m ＋ n = 4） clusters have been carried out.
