Ammonia decomposition in the presence of water vapor I. Nickel, ruthenium and palladium catalysts
1977; Elsevier BV; Volume: 48; Issue: 1-3 Linguagem: Inglês
10.1016/0021-9517(77)90104-x
ISSN1090-2694
Autores Tópico(s)Nanomaterials for catalytic reactions
ResumoThe activity of different catalysts used for the catalytic decomposition of ammonia in the presence of water vapor was studied so as to obtain selective catalysts for the reduction of NO by H2 into N2. Ni, Ru, and Pd base formulas and NiRu and NiPd associations from different preparation methods were investigated. The catalytic species appears to be reduced metal despite the presence of water vapor. Ruthenium proves to be the most active metal, while palladium is inactive. If the initial catalyst is in an oxidized form, reduction by the reaction medium becomes necessary. With NiO this reduction is slow and requires a temperature of about 600 °C, but it appears to be extremely fast with oxidized Ru. With reduced Ru, an activation appears necessary around 530 °C. This activation has been interpreted as expressing a reconstruction of the metal surface. The addition of the noble metals Ru and Pd to nickel oxide enhances the reducibility of this oxide but does not appear to introduce any synergetic effect for the preparation method used.
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