Catalytic decomposition of N2O on supported Rh catalysts

Autor: Stephanus Axnanda, Xiaolai Zheng, Claire Chunjuan Zhang, Olga Gerlach, Andreas Sundermann, Yuejin Li, Ke-Bin Low, Haiyang Zhu
Rok vydání: 2020
Předmět:
Zdroj: Catalysis Today. 355:608-619
ISSN: 0920-5861
DOI: 10.1016/j.cattod.2019.04.063
Popis: Numerous Rh catalysts were evaluated for N2O decomposition for automotive applications. Some Rh-containing spinel materials exhibit excellent fresh activities in the absence of H2O but become inactive after hydrothermal aging or when tested in a wet feed. Rh catalysts supported on zeolites can be very active in a dry feed even after aging but are extremely sensitive to H2O. Rh/CeO2 is an exceptional catalyst for this reaction in the presence of both H2O and O2. Hydrothermal aging (750 °C/20 h) significantly increases its activity. A similar activity enhancement was found by calcining the support before Rh impregnation. XPS results show a surface enrichment of Rh species on the aged Rh/CeO2 catalyst relative to the fresh catalyst. Aberration corrected STEM images reveal that Rh is buried in the bulk on the fresh catalyst and pulled out onto the surface of the support after thermal treatments. All catalysts are inhibited by H2O with the zeolite-based Rh catalysts being the worst. The aged Rh/CeO2 catalyst is less sensitive to H2O relative to others. DRIFTS data show that H2O sensitivity is related to catalyst hydrophilicity; a high coverage of OH groups on a catalyst reduces its N2O decomposition activity. H2-TPR results show that a Rh/CeO2 catalyst can be readily reduced at
Databáze: OpenAIRE
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