MnO2 Nanowire-CeO2 Nanoparticle Composite Catalysts for the Selective Catalytic Reduction of NOx with NH3
- Authors
- Kim, Su Hyo; Park, Bum Chul; Jeon, Yoo Sang; Kim, Young Keun
- Issue Date
- 26-9월-2018
- Publisher
- AMER CHEMICAL SOC
- Keywords
- MnO2 nanowires; CeO2 nanoparticles; composite nanocatalyst; electrodeposition; selective catalytic reduction
- Citation
- ACS APPLIED MATERIALS & INTERFACES, v.10, no.38, pp.32112 - 32119
- Indexed
- SCIE
SCOPUS
- Journal Title
- ACS APPLIED MATERIALS & INTERFACES
- Volume
- 10
- Number
- 38
- Start Page
- 32112
- End Page
- 32119
- URI
- https://scholar.korea.ac.kr/handle/2021.sw.korea/73062
- DOI
- 10.1021/acsami.8b09605
- ISSN
- 1944-8244
- Abstract
- MnOx-based catalysts have been applied to the selective catalytic reduction of NOx with ammonia (NH3) owing to their high NOx removal efficiency and catalytic stability. In general, the fabrication of a variety of nanomaterials in a complex structure requires complicated processes, including heat treatment and a series of cleaning steps. In addition, MnO2 which has diverse polymorphs, exhibits different catalytic effects depending on its crystalline structure. Among them, synthesizing the epsilon-MnO2 phase, which functions as a nanocatalyst, has been the most difficult and has hardly been reported. Here, we report the synthesis of heterostructured composite nanocatalysts consisting of epsilon-MnO2 nanowires (NWs) and CeO2 nanoparticles (NPs) by applying pulsed currents sequentially. This method drastically simplifies the overall process compared to the conventional techniques. Through X-ray diffraction and transmission electron microscopy, it was confirmed that 2-3 nm of CeO2 NPs were formed on the surfaces of the epsilon-MnO2 NWs. The de-NOx efficiency of the nanocatalysts was analyzed in terms of content variation, specific surface area, and the elemental chemical state of the surface. A ceramic filter containing the nanocatalysts shows a high catalytic activity over the broad operating temperature range 100-400 degrees C. In the low-temperature region, epsilon-MnO2 plays a major role in determining the catalytic property, which is consistent with the Brunauer-Emmett-Teller (BET), H-2 temperature-programmed reduction (TPR), and X-ray photoelectron spectroscopy (XPS) results. On the other hand, in the high-temperature region, the efficiency increases gradually as the content of CeO2 increases. The H-2 TPR, NH3-temperature-programmed desorption, and XPS patterns reveal why the composite exhibits such superior characteristics in the temperature range mentioned above.
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