FTIR spectroscopic study of CO oxidation on bimetallic catalysts

• Au–Cu interaction prevents the agglomeration of gold particles on SBA-15 support.
• Cu–Zr interaction determines the strength of CO chemisorption on copper species.
• CO oxidation depends on Au particle size and strength of CO chemisorption on Cu.

SBA-15 with ceria and/or zirconia modified with gold and copper are characterized by spectroscopic methods and their performance for the carbon monoxide oxidation is estimated. Surface properties of the materials and catalysts containing Cu and Au are highlighted and discussed considering the interaction between Ce, Zr, Au and Cu with the emphasis on redox properties. Au–Cu interaction prevents the agglomeration of gold particles at higher temperature. It is shown that gold particle sizes in bimetallic (Au + Cu) samples are smaller than in monometalic (Au) ones. It results in higher activity in CO oxidation. Cu–Zr interaction determines the strength of CO chemisorption on copper species and its further oxidation. The Cu–Zr interaction results also in easy reduction and reoxidation of copper species in the reaction runs. Interaction of copper species with gold and zirconium leads to modification of chemisorption of CO which interacts with active, mobile oxygen transferred from the surface through gold nanoparticles. The right composition of SBA-15 modifiers (cerium and zirconium oxides 1:2) allowed to increase the activity of gold–copper catalysts in CO oxidation.

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