Oxidative coupling of methane over a γ-alumina-supported lead oxide catalyst

✍ Scribed by Sang-Eon Park; Jong-San Chang

• Publisher: Elsevier Science
• Year: 1992
• Tongue: English
• Weight: 984 KB
• Volume: 85
• Category: Article
• ISSN: 0926-860X
• DOI: 10.1016/0926-860x(92)80145-3

✦ Synopsis

Volcano-type patterns, not only in methane conversion but also in C x + hydrocarbons' selectivity, were observed over 60 wt.-% of PbO loaded on y-alumina. The maximum population of PbAl*O, spine1 phase, considered to be formed due to the diffusion of Pb*+ as well as A13+ and O*-ions, was obtained at this loading. This spine1 might attend the oxidative coupling reaction of methane by means of the diffusion of oxygen. However, magnetoplumbite-like phase (PbAl,,O,,) and Pb304, which consists of PbO, and PbO, prevailed with lead aluminate in low loading catalysts. These crystalline phases were drastically changed after reaction, while lead aluminate phase was still important in a 60 wt.-% PbO-A1203 catalyst. This lead aluminate phase would be appropriate in the mobility of oxygen, which might optimally control the coupling activity as a nucleophilic oxide ion. Hence, in the case of y-alumina-supported catalysts the species responsible for the selective oxidative coupling of methane may be lead aluminate and/or lead oxide with a strong support interaction.