PROMOTING EFFECT OF RARE EARTH OXIDES ON Ni/Re_xO_y-Al_2O_3 CATALYST FOR PARTIAL OXIDATION OF METHANE TO SYNTHESIS GAS

IntroductionSynthesisgas(HZ CO)isproducedfrommethanemoshybysteamrefonningwhichsuffersfromlimitationssuchasveryhighenergyrequirements,complicatedequipmentandinstallations,highHZ/COproductratioandpoorselectivityforcarbonmonoxide.Recently,manyresearchershave…

PROMOTING EFFECT OF RARE EARTH OXIDES ON Ni/RexOy-Al2O3 CATALYST FOR PARTIAL OXIDATION OF METHANE TO SYNTHESIS GAS

Partial oxidation of methane to synthesis gas over Ni/Al2O3 and Ni/RExOy-Al2O3 (RExOy is rare earth oxide such as Y2O3, La2O3 and CeO2) catalysts were investigated by using powder X-ray diffraction. The catalytic activity, variation of nickel crystallite size, stability and carbon deposition of catalyst were examined. The presence of rare earth oxides in Ni/Al2O3 catalyst results in a great improvement on the stability of catalyst through interaction between active component Ni and rare earth oxides. The interaction suppresses the growth and the migration of Ni grains. It was found that carbon deposition on Ni/RExOy-Al2O3 catalysts were suppressed and decreased, meantime the catalysts, especially Ni/CeO2-Al2O3, remained activities for partial oxidation of methane. The model of interaction between Ni grains and rare earth oxides may mainly be the embedment, and for Ni/CeO2-Al2O3, there may be a redox circle mechanism of CeO2 besides the embedment.