NiMn2O4 sphere catalyst for the selective catalytic reduction of NO by NH3: Insight into the enhanced activity via solvothermal method. Issue 2 (April 2021)

• Record Type: Journal Article
• Authors: Liu, Jiangning; Wu, Xu; Hou, Benhui; Du, Yali; Liu, Lili; Yang, Baoshuan
• Is Part Of: Journal of environmental chemical engineering. Volume 9:Issue 2(2021)
• Publication Date: 2021-04
• Subjects: NiMn2O4 -- NH3-SCR -- Solvothermal method -- De-NOx performance; Chemical engineering -- Environmental aspects -- Periodicals; Environmental engineering -- Periodicals; Chemical engineering -- Environmental aspects; Environmental engineering; Periodicals; 660.0286
• DOI: 10.1016/j.jece.2021.105152
• Languages: English
• ISSNs: 2213-2929

Abstract

Abstract: Herein, NiMn2 O4 sphere (NiMn2 O4 -S) and NiMn2 O4 particle (NiMn2 O4 -P) were fabricated via solvothermal method and ammonia precipitation method followed by calcination, then the two samples were evaluated as potential candidate catalysts for low temperature NH3 -SCR. Meanwhile, systematical characterizations were employed to establish the relationship between denitrification performance and physiochemical properties. Besides, in-situ DRIFTs and kinetics calculation were performed to reveal the reaction mechanism and the intrinsic catalytic activity. The results verified the preferable catalytic performance of NiMn2 O4 -S with higher than 90% NO conversion at the range of 85–285 °C, and nearly 100% N2 selectivity at 120 °C. The fine catalytic activity might be related to the larger specific surface area, which could contribute to higher Mn 4+ /Mn n+ ratio, ampler Oα, more suitable acid amounts and redox capacity. In-situ DRIFTs revealed that the NH3 -SCR over NiMn2 O4 -S and NiMn2 O4 -P catalysts mainly preceded via Eley–Rideal (E–R) mechanism at 90 °C. The higher TOF values and lower Ea value for NiMn2 O4 -S catalyst further confirmed its excellent de-NOx performance. As compared to NiMn2 O4 -P catalysts, the hierarchical spherical morphology of NiMn2 O4 -S catalyst could generate even more abundant NH3 /NOx adsorption sites, higher reactivity of NH4 + bounded to Brønsted acid sites (NH4 + -BASs) and NH2 species which were conducive to the enhancement of low temperature activity. Graphical Abstract: NiMn2 O4 spinel sphere catalyst with enhanced activity prepared via solvothermal method for NH3 -SCR. ga1 Highlights: NiMn2 O4 spinel catalysts were prepared and employed in NH3 -SCR. The prepared NiMn2 O4 -S catalyst possessed more NH3 /NOx adsorption sites. NH3 -SCR mechanism of NiMn2 O4 catalysts were researched by In-situ DRIFTS. Calculated TOF and Ea reveal the reason for superior de-NOx performance of NiMn2 O4 -S.