NiO-alkaline earth oxide catalysts for oxidative methane-to-syngas conversion: Influence of alkaline earth oxide on the surface properties and temperature-programmed reduction/reaction by H{sub 2} and methane
- National Chemical Lab., Pune (India). Chemical Engineering Div.
Temperature-programmed reaction of pure methane from 100--900 C with NiO-MgO, NiO-CaO, NiO-SrO, and NiO-mixed alkaline earth oxides (viz., MgO-CaO, MgO-SrO, MgO-BaO, CaO-SrO, CaO-BaO, and SrO-BaO) with Ni/alkaline earth element(s) ratio of 1.0 (calcined at 930 C for 4 h) has been studied. Temperature-programmed reduction of these catalysts and NiO-MgO with different Ni/Mg ratios by H{sub 2} from 100 C to 900 C has also been thoroughly investigated. The NiO-CaO, NiO-MgO-CaO, and NiO-MgO catalysts show increasingly superior performance in the oxidative conversion of methane to CO and H{sub 2} at a very low contact time (1 ms). However, the presence of higher alkaline earth oxide (SrO and/or BaO) causes a large decrease or almost complete deactivation of the NiO-containing alkaline earth oxide(s) catalyst for the reaction. The catalysts before and after reduction (by H{sub 2} at 500 C) are characterized for their relative surface composition of Ni and alkaline earth element(s) by XPS. Because of the reduction, the surface Ni/alkaline earth(s) ratio for all the catalysts is decreased; the decrease is, however, very large for the NiO-SrO and all the BaO containing catalysts.
- OSTI ID:
- 659092
- Journal Information:
- Journal of Catalysis, Journal Name: Journal of Catalysis Journal Issue: 2 Vol. 178; ISSN 0021-9517; ISSN JCTLA5
- Country of Publication:
- United States
- Language:
- English
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