Crucial support effect on the durability of Pt/MgAl2O4 for partial oxidation of methane to syngas
Catalyst durability is one of the major problems hindering the commercialization of partial oxidation of methane (POM) for syngas production. We report that a Pt/MgAl 2 O 4 -HS catalyst with the MgAl 2 O 4 -HS support being synthesized via hydrolysis solvothermal (HS) method demonstrates high stability for POM during a 500 h life testing at 900 °C without detectable coke formation, while a Pt/MgAl 2 O 4 -CP counterpart in which MgAl 2 O 4 was prepared by an optimized co-precipitation (CP) method exhibits continuous deactivation accompanied by coking. Using a suite of characterizations incluidng BET, H 2 chemisorption, XRD, STEM, TEM, TG/DTA and TPD of NH 3 and CO 2 , we reveal that the high catalytic durability of the Pt/MgAl 2 O 4 -HS is due to the spinel surface of MgAl 2 O 4 -HS that can efficiently stabilize Pt against sintering. The Pt/MgAl 2 O 4 -CP, however, has defect Al 2 O 3 or MgO-like species on the MgAl 2 O 4 -CP surface, inhibiting its capability to stabilize Pt. We confirm that the POM reaction undergoes a combustion-reforming pathway by monitoring the temperatures and gaseous product compositions along the catalyst bed. These results provide guidance for rational design of a longevity catalyst for POM process.
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