Supported-induced effect on the catalytic properties of Rh and Pt-Rh particles deposited on La2O3 and mixed α-Al2O3-La2O3 in the dry reforming of methane

• Bifunctional mechanism for the CH4/CO2 reaction involving the metal/support interface.
• Detrimental effect of surface Pt enrichment in bimetallic Pt-Rh particles in the dry reforming reaction.
• Stabilization on noble metal dispersion on Pt-Rh/Al2O3-La2O3 via stronger interaction with composite LaAlOx microstructure.

Rhodium and platinum-rhodium based catalysts supported on La2O3 and Al2O3 doped with La2O3 were investigated in the dry reforming of methane. The textural and structural properties were studied on calcined, reduced and used catalysts from nitrogen physisorption, X-ray diffraction, XPS, SEM, H2- and O2-temperature-programmed experiments. Rh is intrinsically more active than Pt independently of the support composition. Different types of interactions occur when Rh is incorporated in Pt on La2O3 and La-modified α-Al2O3 supports with the observations of synergistic effects on the activity of Pt-Rh/Al2O3-La2O3 for methane conversion. Correlations between catalytic properties with structural and surface properties have been tentatively established and are discussed. A detrimental effect of alloyed Pt-Rh particles on La2O3 and a beneficial effect on the catalytic activity of Pt-Rh/Al2O3-La2O3 due to the formation of possible composite microstructures combining noble metals and the elements of the support is reported.

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