Catalytic CO2 reforming of CH4 over MgAl2O4 supported Ni-Co catalysts for the syngas production

Abstract

Ni, Co and Ni–Co bimetallic catalysts of different ratios were synthesized by the Incipient Wetness Impregnation Method (IWI) over Magnesium Aluminate support, keeping the total metal loading 15 wt.%, characterized and tested for the reforming of methane with carbon dioxide at 873 K and 1 atm pressure. Magnesium Aluminate supported catalysts were also compared with Al2O3 supported Ni catalysts with similar metal loading. The results obtained revealed that MgAl2O4 exhibited excellent thermal stability as compared to Al2O3 as support at higher temperatures. Ni–Co catalyst, with an explicit Ni:Co (3:1) ratio for the 75Ni25Co/MgAl2O4 provided the highest CH4 conversion and was about 1.82 times that of the 100Ni/MgAl2O4; CO2 conversion also followed similar trends. Co-existence of Ni and Co with synergic effect in an explicit Ni:Co (3:1) ratio reduced the reduction temperature and increased the amount of metal in 75Ni25Co/MgAl2O4. CH4 and CO2 conversions, TOFDRM, H2: CO ratios and catalyst deactivations were related to the concentrations of the Ni–Co and particularly an explicit ratio of 3:1 for the Ni:Co in 75Ni25Co/MgAl2O4 catalyst provided the best initial & final conversions, TOFDRM and H2:CO ratio. Detail carbon analysis suggested that the type of coke deposited on 75Ni25Co/MgAl2O4 after the DRM reaction is of the same nature and are originating from the CH4 cracking reaction and are of reactive type.