Silver-manganese mixed oxide with crednerite structure as a catalyst for low-temperature catalytic CO oxidation

Unraveling the Structure–Activity Relationship of Delafossite Ag2CuMnO4 in CO Oxidation at Subambient Temperatures

“…Second, manganese within the CuMnO 2 structure is not characterized by the variety of charge states, being presented predominantly in the Mn 3+ form . Manganese redox lability behaves similarly in the case of AgMnO 2 oxide with a crednerite structure, demonstrating relatively low catalytic activity ( T 50 ∼ 60 °C) under the same catalytic conditions . It is known that charge transfer in the octahedral layer occurs through polaron hopping of electron holes between the Mn 3+ and Mn 4+ ions, which in the case of a spinel structure is achieved through the disproportionation 2Mn 3+ = Mn 4+ + Mn 2+ . , A similar process is likely to occur in the case of a ternary oxide, where the B cations can be represented not only by a combination of Cu 2+ /Mn 4+ species but also as Mn 3+ /Mn 3+ pair, especially in the case of Mn-enriched surface at T ≤ 250 °C (Figure ).…”