Effect of the Na addition to PrOx/MgO on the Reactivity and Selectivity in the Oxidative Coupling of Methane

G. BARONETTI; C.L. PADRÓ; A.A. CASTRO; O.A. SCELZA

STUDIES IN SURFACE SCIENCE AND CATALYSIS

Elsevier

Lugar: Amsterdam; Año: 1998 vol. 119 p. 337 - 342

0167-2991

The Na addition to PrOx (10%wt)/MgO produces a very important modification in the activity and selectivity to ethane + ethylene in the oxidative coupling of methane (OCM), which was carried out by injecting pulses of pure methane on the samples at 1023 K. The specific activity decreases as the Na content increases, but the selectivity to C2 dramatically increases. According to XRD, SEM-EDX and XPS results, the bechaviour in OCM can be related to the different surface species. For low Na contents, reduced surface PrOx species were found, while a Pr-Na compound was detected by XRD for high Na concentrations in the samples. The high initial selectivity to C2 hydrocarbons for samples with high Na/Pr ratio could be related to the presence of the above mentioned Pr-Na species.