Enhancement of the CO oxidation reaction: Impact of the precursor addition sequence on the synthesis of Au-Co₃O₄/Al₂O₃ catalysts

In the present work, it is demonstrated that a synergistic effect on the CO oxidation reaction can be achieved depending on the cobalt loading and deposition order of metal precursors employed in the synthesis of Au-Co₃O₄/Al₂O₃ catalysts by the deposition precipitation with urea method. The atomic arrangement of Au and Co₃O₄ exerts an important influence on the catalytic activity. Intermediate reaction species in the studied systems were identified through DRIFTS spectroscopy, which provided insights into the reaction mechanism. The formation of Au⁰ and Au^δ− as active sites for CO oxidation, along with mono- and bidentate bicarbonate ligands as active reaction intermediates, was elucidated.