Design considerations for low-temperature hydrocarbon oxidation reactions on Pd based catalysts
Design considerations for low-temperature hydrocarbon oxidation reactions on Pd based catalysts
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DOI：
10.1016/j.apcatb.2018.05.049
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发表时间：
2018-11-15
影响因子：
22.1
通讯作者：
Datye, Abhaya K.
中科院分区：
文献类型：
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作者：
Xiong, Haifeng;Wiebenga, Michelle H.;Datye, Abhaya K.
钯基催化剂因其在碳氢化合物氧化反应中的催化活性而广为人知。需要开发在低温(<；300摄氏度)下执行氧化的催化剂，特别是用于未来的高效率内燃机。在本研究中，我们研究了在此温度范围内Pd氧化态对三种不同碳氢化合物(甲烷、丙烷和丙烯)的氧化作用。对于每种碳氢化合物，还原后的Pd催化剂氧化后的活性均高于相同催化剂。此外，当还原催化剂在贫氧条件下进行测试时，由于生成了PdO，其烃类氧化活性下降。添加铂有助于将钯保持在还原状态，即使在贫化条件下也是如此，这是与单独添加铂或钯相比，铂-钯催化剂性能提高的主要原因。通过X射线近边吸收光谱(XANES)和程序升温还原(TPR)实验，结合活性测试，了解Pd的氧化状态对碳氢化合物氧化性能的影响。本研究对低温碳氢化合物氧化Pd催化剂的开发和操作具有指导意义。
Palladium-based catalysts are well known for their catalytic activity in hydrocarbon oxidation reactions in exhaust emission control. There is a need to develop catalysts that perform oxidation at low temperatures (< 300 degrees C), especially for future high efficiency combustion engines. In the present study, we investigate the role of Pd oxidation state in this temperature range for the oxidation of three different hydrocarbons (methane, propane and propylene). For each of these hydrocarbons, the reduced Pd catalyst was more active than the same catalyst after oxidation. Furthermore, when the reduced catalyst was tested under lean conditions, the activity for hydrocarbon oxidation declined due to formation of PdO. The addition of Pt helped to maintain Pd in a reduced state, even under lean conditions, and this is a major reason for improved performance of Pt-Pd catalysts compared to Pt or Pd alone. X-ray absorption near edge spectra (XANES) and temperature programmed reduction (TPR) experiments were used along with activity testing to understand the impact of the oxidation state of Pd on hydrocarbon oxidation performance. This study provides guidance in the development and operation of Pd catalysts for low temperature hydrocarbon oxidation.