Nanometric Iridium Overlayer Catalysts for High-Turnover NH₃ Oxidation with Suppressed N₂O Formation.

ABSTRACT: In the present study, we prepared a 12 nm thick Ir overlayer via pulsed cathodic arc plasma deposition on a 50 μm thick Fe-Cr-Al metal (SUS) foil. Using this thin-film catalyst made NH₃-O₂ reactions more environmentally benign due to a much lower selectivity for undesirable N₂O (<5%) than that of a Pt overlayer (∼70%) at 225 °C. Despite its small surface area, Ir/SUS exhibited promising activity as an ammonia slip catalyst according to a turnover frequency (TOF) >70-fold greater than that observed with conventional Ir nanoparticle catalysts supported on γ-Al₂O₃. We found that the high-TOF NH₃ oxidation was associated with the stability of the metallic Ir surface against oxidation by excess O₂ present in simulated

SUBMITTER: Machida M 

PROVIDER: S-EPMC7758949 | biostudies-literature | 2020 Dec

REPOSITORIES: biostudies-literature