Partial Oxidation of Methane to Synthesis Gas over Oxidized Diamond Supported Catalysts—Catalytic Behavior of Nickel and Cobalt Species
| Autor: | Kiyoharu Nakagawa, Toshimitsu Suzuki, Toru Konishi, Hiroaki Nishimoto, Na-oki Ikenaga |
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| Rok vydání: | 2005 |
| Předmět: | |
| Zdroj: | Journal of the Japan Petroleum Institute. 48:290-300 |
| ISSN: | 1349-273X 1346-8804 |
| DOI: | 10.1627/jpi.48.290 |
| Popis: | Characterization of nickel and cobalt catalysts supported on oxidized diamond (O-dia) in the partial oxidation of methane to synthesis gas was carried out by X-ray photoelectron spectroscopy (XPS) and the transient response pulse technique. Carbon deposition occurred on nickel/O-dia, but not on cobalt/O-dia catalyst at 873 K throughout prolonged reaction. XPS analyses observed partially reduced nickel oxides on nickel/O-dia catalyst after reaction with methane/oxygen (5/1) at 873 K. Co(0), partially reduced cobalt oxide, and Co(III) oxide phases were found on cobalt/O-dia catalyst after reaction at 873 K. Transient response methane/oxygen (2/1) pulse studies found a large amount of hydrogen production occurred immediately at 873 K over the nickel/O-dia catalyst. However, a very small amount of hydrogen production was seen over the cobalt/O-dia catalyst, indicating that nickel and cobalt species supported on O-dia exhibited different behavior. Transient response of the catalyst bed temperature found that endothermic reaction occurred on the nickel/O-dia catalyst at 873 K, but exothermic reaction proceeded on the cobalt/O-dia catalyst. These results suggest that methane decomposition to hydrogen is the primary reaction path over nickel/O-dia catalyst, whereas complete oxidation is the primary reaction followed by steam and carbon dioxide reforming to produce synthesis gas over the cobalt/O-dia catalyst. |
| Databáze: | OpenAIRE |
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