Platinum‐Iron(II) Oxide Sites Directly Responsible for Preferential Carbon Monoxide Oxidation at Ambient Temperature: An Operando X‐ray Absorption Spectroscopy Study**.

Sadykov, Ilia I.; Sushkevich, Vitaly L.; Krumeich, Frank; Nuguid, Rob Jeremiah G.; van Bokhoven, Jeroen A.; Nachtegaal, Maarten; Safonova, Olga V.

Operando X‐ray absorption spectroscopy identified that the concentration of Fe2 species in the working state‐of‐the‐art Pt−FeOx catalysts quantitatively correlates to their preferential carbon monoxide oxidation steady‐state reaction rate at ambient temperature. Deactivation of such catalysts with time on stream originates from irreversible oxidation of active Fe2 sites. The active Fe2 species are presumably Fe 2O−2 clusters in contact with platinum nanoparticles; they coexist with spectator trivalent oxidic iron (Fe3 ) and metallic iron (Fe0) partially alloyed with platinum. The concentration of active sites and, therefore, the catalyst activity strongly depends on the pretreatment conditions. Fe2 is the resting state of the active sites in the preferential carbon monoxide oxidation cycle.

OXIDATION of carbon monoxide; X-ray absorption; X-ray spectroscopy; CATALYST poisoning; PLATINUM nanoparticles; PLATINUM alloys

Angewandte Chemie, 2023, Vol 135, Issue 1, p1

0044-8249

Academic Journal

10.1002/ange.202214032