Different Reaction Mechanisms of Ammonia Oxidation Reaction on Pt/Al2O3 and Pt/CeZrO2 with Various Pt States
| Autor: | Mengmeng Sun, Jingying Liu, Xiaoqing Zhao, Chang Song, Yaoqiang Chen, Hanbing Rao, Haidi Xu, Yoshito Ogata |
|---|---|
| Rok vydání: | 2019 |
| Předmět: |
Reaction mechanism
Materials science Inorganic chemistry chemistry.chemical_element 02 engineering and technology 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences Oxygen Redox 0104 chemical sciences Catalysis Ammonia chemistry.chemical_compound chemistry Transmission electron microscopy General Materials Science 0210 nano-technology Selectivity Platinum |
| Zdroj: | ACS Applied Materials & Interfaces. 11:23102-23111 |
| ISSN: | 1944-8252 1944-8244 |
| Popis: | NH3 emissions were limited strictly because of the threat for human health and sustainable development. Pt/Al2O3 and Pt/CeZrO2 were prepared by the impregnation method. Differences in surface chemical states, reduction ability, acid properties, morphological properties, reaction mechanisms, and ammonia oxidation activity were studied. It indicated that Pt species states were affected by different metal-support interactions. The homogeneously dispersed Pt species over Pt/Al2O3 exposed Pt(111) because of weak metal-support interactions; there even existed an obvious interface between Pt and Al2O3. While obscure even an overlapped interface was observed over Pt/CeZrO2, resulting in the formation of PtO because of the oxygen migration from CeZrO2 to Pt species (confirmed by CO-FTIR, the cycled H2-TPR and transmission electron microscopy results). It was noteworthy that different reaction mechanisms were induced by different states of Pt species; NH was the key intermediate species for ammonia oxidation reaction over Pt/Al2O3, but two kinds of intermediates, N2H4 and HNO, were observed for Pt/CeZrO2. It consequently resulted in the obvious distinction of the NH3-SCO catalytic performance; the light-off temperatures of NH3 over Pt/Al2O3 and Pt/CeZrO2 were 231 and 275 °C, respectively, while the maximum N2 selectivity (65%) was obtained over Pt/CeZrO2, it was obviously better than that over Pt/Al2O3. |
| Databáze: | OpenAIRE |
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