...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>The journal of physical chemistry, B. Condensed matter, materials, surfaces, interfaces & biophysical >XPS Study of the Adsorption of SO_2 and NH_3 over Supported Tin Dioxide Catalysts Used in de-NOx Catalytic Reaction
【24h】

XPS Study of the Adsorption of SO_2 and NH_3 over Supported Tin Dioxide Catalysts Used in de-NOx Catalytic Reaction

机译：XPS法研究脱NOx催化的负载型二氧化锡催化剂对SO_2和NH_3的吸附

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Alumina and titania supported tin dioxide catalysts presenting various Sn loadings were prepared by impregnation. The acidity and basicity of the samples were determined by adsorption of ammonia and sulfur dioxide, respectively, using adsorption microcalonmetry and X-ray photoelectron spectroscopy. The surface reactivity of the samples and the chemical composition of the adsorbed species were determined as well as the heats of adsorption of the probe molecules. The catalysts were tested in the selective catalytic reduction of NO by C_2H_4. Both calorimetry and XPS experiments have shown that the SnO2/TiO2 series of samples was markedly more acidic than the Sn0_2/A1_2O_3 series, as the N/(Ti+Sn) molar ratios were noticeably higher than the corresponding N(Al+Sn) ratios. The number of acidic sites seemed to increase with the tin content when tin dioxide was well dispersed on the support. They are of Lewis type. It was shown that sulfur dioxide adsorption led to the formation of three types of species: S0_2, sulfites, and sulfates. The basicity of the Sn0_2/A1_20_3 series of samples was weaker than that of the alumina support and passed through a minimum around 12 wt % Sn. On the contrary, as the acidity, the basicity of the SnTi series did not seem dependent on the Sn concentration. This can be correlated to the bad dispersion of SnO_2 on TiO_2. In the NO reduction by C_2H_4 reaction, the turnover frequency mainly depends on the Sn dispersion, and the Sn centers are very active even at low amounts.
机译：通过浸渍制备具有各种Sn负载的氧化铝和二氧化钛负载的二氧化锡催化剂。样品的酸度和碱度分别通过吸附微热量法和X射线光电子能谱法通过氨和二氧化硫的吸附来确定。测定样品的表面反应性和被吸附物质的化学组成以及探针分子的吸附热。测试了催化剂通过C_2H_4选择性催化还原NO的能力。量热法和XPS实验均表明，SnO2 / TiO2系列样品的酸性明显高于Sn0_2 / A1_2O_3系列，因为N /（Ti + Sn）摩尔比明显高于相应的N（Al + Sn）比。 。当二氧化锡很好地分散在载体上时，酸性部位的数目似乎随锡含量的增加而增加。它们是路易斯型的。结果表明，二氧化硫的吸附导致形成三种类型的物质：SO_2，亚硫酸盐和硫酸盐。 Sn0_2 / A1_20_3系列样品的碱度比氧化铝载体的碱度弱，并且通过的最小碱度约为12 wt％。相反，作为酸度，SnTi系列的碱性似乎不依赖于Sn浓度。这可能与SnO_2在TiO_2上的分散性差有关。在通过C_2H_4反应进行的NO还原中，周转频率主要取决于Sn的分散，并且Sn中心即使在少量时也非常活跃。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号