Applied Catalysis A: General, Vol.154, No.1-2, 17-27, 1997
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 thermal stability and the carbon-deposition resistance during the partial oxidation of methane to syngas (POM) reaction at high temperature. The reaction performance, thermal stability, structure, dispersity of nickel and carbon-deposition of the modified NiO/Al2O3 catalyst and unmodified NiO/Al2O3 catalyst were investigated by a series of characterization techniques including flow-reaction, BET, XRD, CO chemisorption and TG analysis. The results indicated that the modification with alkali metal oxide and rare-earth metal oxide improves the dispersion of active component nickel and the activity for the POM reaction over the nickel-based catalysts, and enhances their thermal stability during high temperature reaction and the ability to suppress the carbon-deposition over the nickel-based catalysts during the POM reaction. The nickel-based catalysts modified by alkali metal oxide and rare-earth metal oxide 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.
Keywords:CARBON DEPOSITION;SYNTHESIS GAS;SUPPORTS;GAMMA-AL2O3;CONVERSION;ADDITIVES;MONOXIDE;HYDROGEN