PARTIAL OXIDATION OF METHANE TO SYNGAS OVER NICKEL-BASED CATALYSTS MODIFIED BY ALKALI-METAL OXIDE AND RARE-EARTH-METAL OXIDE

The NiO/Al2O3 catalyst was modified by alkali metal oxide (Li, Na, K) and rare-earth metal oxide (La, Ce, Y, Sm) in order to improve the the rmal stability and the carbon-deposition resistance during the partial oxidation of methane to syngas (POM) reaction at high temperature. Th e reaction performance, thermal stability, structure, dispersity of ni ckel and carbon-deposition of the modified NiO/Al2O3 catalyst and unmo dified NiO/Al2O3 catalyst were investigated by a series of characteriz ation techniques including flow-reaction, BET, XRD, CO chemisorption a nd TG analysis. The results indicated that the modification with alkal i metal oxide and rare-earth metal oxide improves the dispersion of ac tive component nickel and the activity for the POM reaction over the n ickel-based catalysts, and enhances their thermal stability during hig h temperature reaction and the ability to suppress the carbon-depositi on over the nickel-based catalysts during the POM reaction. The nickel -based catalysts modified by alkali metal oxide and rare-earth metal o xide have excellent POM reaction performance (CH4 conversion of 94.8%, CO selectivity of 98.1%, 2.7 x 10(4) 1/kg.h), excellent stability and carbon-deposition resistance.