| Autor: |
Murata, Kazumasa, Arai, Keita, Kondo, Nao, Manabe, Ryo, Yumura, Takashi, Hosokawa, Saburo |
| Zdroj: |
Catalysis Science & Technology; 2024, Vol. 14 Issue: 11 p3253-3264, 12p |
| Abstrakt: |
The production of high-value-added chemicals and their raw materials by partial oxidation of methane (POM) is advantageous. The screening of 31 simple oxide catalysts for direct POM showed that ZrO2had the highest syngas yield (CO and H2) and was thus a promising catalyst. Kinetic analysis indicated that POM over the ZrO2catalyst proceeded in a Langmuir–Hinshelwood mechanism and that CH4activation was the rate-limiting step. Density functional theory calculations showed that CH4was activated on coordinatively unsaturated Zr4+cations formed by the dehydration of the hydroxyl groups on the ZrO2surface. In situdiffuse reflectance infrared Fourier transform spectroscopy revealed that CH4was converted into CO and H2through CH4-oxygenated intermediates, such as methoxy and formate species. The CH4-oxygenated intermediates on the ZrO2catalyst were closely related to the catalytic performance of the oxide catalysts in POM. A comprehensive investigation of the POM reaction over ZrO2-based catalysts was then conducted. ZrO2modification with tungsten oxide (WOx) or lanthanum oxide (LaOx) was examined to determine their ability to improve the catalytic properties of ZrO2for POM. ZrO2modification with WOxand LaOxenhanced its acidity and basicity, respectively. CO selectivity was increased by modifying ZrO2with a small amount of WOx. Moreover, modification with LaOxincreased CH4conversion and H2yield at low temperatures. |
| Databáze: |
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