Effect and behavior of cerium oxide in Ni/γ-Al_2O_3 catalysts on autothermal reforming of methane:CeAlO_3 formation and its role on activity

摘要

Nickel supported γ-alumina (N1/γ-AI_2O_3) catalysts are well-known to be highly active on the autothermal reforming of methane, but to be unstable due to coke deposition. Cerium oxide (CeO_2) is one of promising promoter to overcome the fast deactivation of nickel-based catalysts by coke formation. Herein, catalytic behavior of CeO_2 over Ni/-y-Al_2O_3 catalysts on the autothermal reforming of methane was investigated. The catalytic activity was maintained for 100 h with H_2/CO molar ratio of 1.9. The formation of CeAIO_3 is observed at the reduction and reaction conditions. In this work, it was found that the formation of CeAlO_3 promoted the catalytic oxidation toward CO_2 and prevented the formation of a-Al_2O_3 and nickel-aluminate, resulting in stable activity for autothermal reforming of methane.