Synthesis gas production via propane dry (CO2) reforming: Influence of potassium promotion on bimetallic Mo-Ni/Al2O3

The effect of K-promotion on alumina-supported Mo-Ni catalyst for propane dry reforming has been investigated in a quartz fixed-bed reactor at 823–973 K and 0.1 MPa. K-promotion increased BET surface area, pore volume and metal dispersion of the catalyst. The acid:basic site ratio of the K-containing catalyst was lower than in the undoped Mo-Ni counterpart. The two catalysts have comparable propane dry reforming performance although CO formation was greater on the promoted catalyst. It was, however, accompanied by poorer H2 production rate. The optimum CO2:C3H8 ratio, Ropt = 2, was below the stoichiometric value for H2 on both catalysts but at about 3 for CO production. Potassium addition reduced carbon deposition on the used catalyst and improved its stability. Post-reaction characterisation by double cycle TPR-TPO runs confirmed the existence of at least two types of carbonaceous species (atomic and dehydropolymerised, aged) in the used catalysts. The physicochemical properties of the regenerated catalysts could not be completely restored to the initial state but depended on the reforming conditions.

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► The new Mo-Ni/Al2O3 and its K-promoted counterpart have propane dry reforming activity.
► K-promotion decreased carbon deposition and improved catalyst stability.
► Maximum H2 production rate required CO2:C3H8 ratio lower than the stoichiometric value of 3.
► CH4 formation decreased with increasing temperature parallel to carbon deposition trend.