Manganese Oxide Overlayers Promote CO Oxidation on Pt

The influence of manganese oxide on CO oxidation over Pt was investigated. Pt/Al2O3 catalysts were modified by the atomic layer deposition (ALD) of MnOx with deposition before or after addition of Pt, and the results were compared to those with an unmodified Pt/Al2O3 catalyst. The addition of MnOx improved the catalyst durability, mitigating the agglomeration of Pt particles after thermal aging at 1073 K. The addition of MnOx also promoted CO oxidation rates by creating active Pt–MnOx interfacial sites despite the fact that CO adsorption was suppressed after high-temperature calcination. Transmission electron microscopy (TEM) showed that Pt was uniformly covered by a thin film of MnOx after calcination. The implications of these results with regard to understanding the MnOx promotion of Pt catalysts are discussed.