...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Catalysis science & technology >Au-2(+) cannot catalyze conversion of methane to ethene at low temperature
【24h】

Au-2(+) cannot catalyze conversion of methane to ethene at low temperature

机译：Au-2(+)不能催化甲烷转化低温乙烯

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

The previously reported conversion of methane to ethene catalyzed by Au2 + at thermal energies, at odds with established thermodynamics, is investigated through a combination of experiments under both singlecollision conditions using a guided ion beam tandem mass spectrometer (GIBMS) apparatus and at higher pressures using a selected-ion flow tube (SIFT) apparatus, as well as through density functional calculations. Production of Au2.C2H4)+ (or m/ z 422) or Au2.C2D4)+ (or m/ z 426) is significantly lower in the higher pressure SIFT experiments relative to previously reported results. The amount observed is consistent with a pathway initiating from a small fraction of a reactive species, potentially electronically excited Au2 +* or Au2O+, isobaric with Au2.CH4)+. Extensive theoretical exploration of the potential energy surface for Au2.CH4)+ + CH4 shows no low-energy pathway that is consistent with ethene formation, with prohibitive barriers of 1-2 eV calculated along all identified reaction coordinates, consistent with previous calculations. GIBMS data do show the production of m/ z 422 in the reaction of Au2.CH4)+ + CH4, consistent with the proposed key intermediate, but also provide evidence that this observed species is Au2.CO)+ arising from Au2O+, not Au2.C2H4)+ arising from Au2.CH4)+. The present results are consistent with the established thermochemistry for methane-to-ethene conversion, which unambiguously demonstrates that such conversion cannot proceed at thermal energies regardless of the presence of Au2
机译：之前报道转换的甲烷乙烯催化Au2 +热能量,与建立了热力学,通过结合实验调查在两个singlecollision条件下使用引导离子束串联质谱仪(本)设备和使用在更高的压力selected-ion流管(筛选)装置,通过密度泛函计算。生产Au2.C2H4) +(或m / z 422)或Au2.C2D4) +(或m / z 426)显著降低在筛选实验相对较高的压力之前报道的结果。观察是一致的路径开始一小部分的活性物种,Au2 + *或潜在电子兴奋与Au2.CH4) + Au2O +,等压。理论探索的潜在能量表面Au2.CH4) + + CH4低能途径与乙烯形成一致,1 - 2 eV计算限制性壁垒在所有确认反应坐标,符合之前的计算。做节目生产的m / z 422反应Au2.CH4) + + CH4,符合提出关键的中间,但也提供证据表明,这个观察到的物种是Au2.CO) +因Au2O +,而不是Au2.C2H4) +引起的Au2.CH4) +。建立了热化学的methane-to-ethene转换,这毫无疑问表明这些转换无法继续在热的能量的存在无关Au2

著录项

相似文献

  • 外文文献
  • 中文文献
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