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首页> 外文期刊>The journal of physical chemistry, A. Molecules, spectroscopy, kinetics, environment, & general theory >CO-Free Hydrogen Production for Fuel Cell Applications over Au/CeO2 Catalysts: FTIR Insight into the Role of Dopant
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CO-Free Hydrogen Production for Fuel Cell Applications over Au/CeO2 Catalysts: FTIR Insight into the Role of Dopant

机译：在Au / CeO2催化剂上用于燃料电池的无二氧化碳氢生产：FTIR深入了解掺杂剂的作用

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The impact of ceria doping by Zn (atomic ratio Zn/(Zn + Ce) ) 0.05) on the structural and catalytic properties of Au/CeO2 catalyst was studied. The ceria modification influenced the catalytic activity toward purification of hydrogen via water-gas shift (WGS) and preferential CO oxidation (PROX) reactions in a different way: it diminished the WGS activity and improved the PROX performance. A characterization by FTIR spectroscopy was conducted to explain differences in the catalytic performance. The nature of gold active species after different pretreatments, under different atmospheres (H2, D2), and after admission of CO and its subsequent interaction with 18O2 was investigated. Evidence has been found of the dissociation of hydrogen at room temperature on gold, producing on the oxidized sample a broad absorption assigned to Au-OH vibrations, whereas on the reduced one, bands at 3200 and 1800 cm-1 ascribed, respectively, to Au-OH and Au-H species have been detected. For the first time, the formation of Au-hydride on supported heterogeneous catalysts was proposed. These features were stronger on the Au/CeO2 sample than on the Au/Zn-CeO2 sample. The availability of highly dispersed gold clusters in contact with oxygen vacancies on the ceria surface could contribute to higher WGS activity, whereas the steps of small gold particles are the active sites for both CO and oxygen activation during the PROX reaction.
机译：研究了Zn掺杂二氧化铈（原子比Zn /（Zn + Ce））0.05对Au / CeO2催化剂结构和催化性能的影响。二氧化铈的修饰以不同的方式影响了通过水煤气变换（WGS）和优先的CO氧化（PROX）反应对氢提纯的催化活性：它降低了WGS活性并提高了PROX性能。通过FTIR光谱进行了表征，以解释催化性能的差异。研究了在不同的预处理，不同的气氛（H2，D2）下以及吸收了CO后金活性物种的性质及其与18O2的后续相互作用。已经发现有证据表明室温下金会发生氢离解，在氧化的样品上会产生与Au-OH振动有关的宽吸收，而在还原后的样品上，会在3200和1800 cm-1处分别归因于Au。已检测到-OH和Au-H物质。首次提出在负载型多相催化剂上形成金氢化物。这些特征在Au / CeO2样品上比在Au / Zn-CeO2样品上更强。与氧化铈表面上的氧空位接触的高度分散的金簇的可用性可能有助于更高的WGS活性，而小的金颗粒的台阶是PROX反应期间CO和氧活化的活性位点。

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