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首页> 外文期刊>Physical chemistry chemical physics: PCCP >Activation and isomerization of n-butane on sulfated zirconia model systems - an integrated study across the materials and pressure gaps
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Activation and isomerization of n-butane on sulfated zirconia model systems - an integrated study across the materials and pressure gaps

机译：正丁烷在硫酸化氧化锆模型系统上的活化和异构化-跨材料和压差的综合研究

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Butane activation has been studied using three types of sulfated zirconia materials, single crystalline epitaxial films, nanocrystalline films, and powders. A surface phase diagram of zirconia in interaction with SO3 and water was established by DFT calculations, which was verified by LEED investigations on single-crystalline films and by IR spectroscopy on powders. At high sulfate surface densities a pyrosulfate species is the prevailing structure in the dehydrated state; if such species are absent, the materials are inactive. Theory and experiment show that the pyrosulfate can react with butane to give butene, H2O and SO2, hence butane can be activated via oxidative dehydrogenation. This reaction occurred on all investigated materials; however, isomerization could only be proven for powders. Transient and equilibrium adsorption measurements in a wide pressure and temperature range ( isobars measured via UPS on nanocrystalline films, microcalorimetry and temporal analysis of products measurements on powders) show weak and reversible interaction of butane with a majority of sites but reactive interaction with < 5 mmol g(-1) sites. Consistently, the catalysts could be poisoned by adding sodium to the surface in a ratio S/Na = 35. Future research will have to clarify what distinguishes these few sites.
机译：已经使用三种类型的硫酸化氧化锆材料，单晶外延膜，纳米晶膜和粉末研究了丁烷活化。通过DFT计算建立了氧化锆与SO3和水相互作用的表面相图，并通过LEED对单晶膜的研究和对粉末的IR光谱进行了验证。在高硫酸盐表面密度下，焦硫酸盐是脱水状态下的主要结构。如果缺少此类物质，则说明该材料是非活性的。理论和实验表明，焦硫酸盐可与丁烷反应生成丁烯，H2O和SO2，因此丁烷可通过氧化脱氢活化。该反应发生在所有研究的材料上。但是，异构化只能用于粉末。在很宽的压力和温度范围内进行瞬态和平衡吸附测量（通过UPS在纳米晶体薄膜上测量的等压线，粉末量热法和粉末上产品测量的时间分析）显示丁烷与大多数位点的相互作用弱且可逆，但反应性相互作用<5 mmol g（-1）个网站。始终如一地，可以通过以S / Na = 35的比例向表面添加钠来中毒催化剂。未来的研究将必须弄清楚区别这几个部位的原因。

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