title: Scale-Activity Relationship of MnOx-FeOyNanocage Catalysts Derived from Prussian Blue Analogues for Low-Temperature NO Reduction: Experimental and DFT Studies.
abstract: Size effects have been recognized to promote the catalytic activity and selectivity of metal oxide particles. So far, limited works and studies are conducted to investigate the size effect of metal oxide with the tailored shape in the selective catalytic reduction of NOxwith NH3(NH3-SCR). Herein, the MnOx-FeOynanocage catalysts with varied scales (0.25, 0.5, 1, and 2 μm) were synthesized via a Prussian blue analogue (PBA)-derived method and used for NH3-SCR of NO. By preforming a series of the activity tests over the nanocages with different scales, the NH3-SCR activity of 0.5 μm MnOx-FeOynanocage catalysts exhibits the highest deNOxactivity in the temperature range of 80-200 °C owing to more preferable physical and chemical properties. It has been demonstrated that there is a strong interaction among Mn and Fe cations in the 0.5 μm MnOx-FeOynanocages. Moreover, the H2-TPR and XPS analysis prove 0.5 μm nanocages exhibit excellent redox properties, which contribute to the higher conservation of NOx. Through the DFT studies, it is also demonstrated that the 0.5 μm MnOx-FeOynanocage catalysts could provide more preferable electronic charge, which gives rise to the varied adsorption behavior of the NH3species and NOxspecies compared to the nanocages with other scales. The in situ DRIFTs were also employed to evaluate the adsorption status of NH3with NOxspecies over MnOx-FeOynanocage catalysts with varied scales. Finally, the scale-activity relationship of the MnOx-FeOynanocage catalysts and their corresponding activities are also established. The deep insight into the scale-activity relationship of the PBA-derived MnOx-FeOynanocage catalyst paves the way for developing and designing highly efficient Mn-based catalyst at lower temperature.
authors.affiliation: School of Environmental and Chemical Engineering, Research Center of Nano Science and Technology, Shanghai University , Shanghai 200444, P. R. China.
authors.forename: Lijun
authors.initials: L
authors.lastname: Yan
authors.affiliation: School of Environmental and Chemical Engineering, Research Center of Nano Science and Technology, Shanghai University , Shanghai 200444, P. R. China.
authors.forename: Yangyang
authors.initials: Y
authors.lastname: Liu
authors.affiliation: School of Environmental and Chemical Engineering, Research Center of Nano Science and Technology, Shanghai University , Shanghai 200444, P. R. China.
authors.forename: Kaiwen
authors.initials: K
authors.lastname: Zha
authors.affiliation: School of Environmental and Chemical Engineering, Research Center of Nano Science and Technology, Shanghai University , Shanghai 200444, P. R. China.
authors.forename: Hongrui
authors.initials: H
authors.lastname: Li
authors.affiliation: School of Environmental and Chemical Engineering, Research Center of Nano Science and Technology, Shanghai University , Shanghai 200444, P. R. China.
authors.forename: Liyi
authors.initials: L
authors.lastname: Shi
authors.affiliation: School of Environmental and Chemical Engineering, Research Center of Nano Science and Technology, Shanghai University , Shanghai 200444, P. R. China.
authors.forename: Dengsong
authors.identifier: http://orcid.org/0000-0003-4280-0068
authors.initials: D
authors.lastname: Zhang
keywords: NH3−SCR; NOx; low temperature; size-dependent; structure−activity