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Insight into the synergism between MnO 2 and acid sites over Mn-SiO 2 @TiO 2 nano-cups for low-temperature selective catalytic reduction of NO with NH 3 .

Siyi ZhengLei SongSiyang TangChangjun LiuHairong YueBin Liang
Published in: RSC advances (2018)
The rational synthesis of low-temperature catalysts with high catalytic activity and stability is highly desirable for the selective catalytic reduction of NO with NH 3 . Here we synthesized a Mn-SiO 2 /TiO 2 nano-cup catalyst via the coating of the mesoporous TiO 2 layers on SiO 2 spheres and subsequent inlay of MnO 2 nanoparticles in the narrow annulus. This catalyst exhibited superior catalytic SCR activities and stability for low-temperature selective catalytic reduction of NO with NH 3 , with NO conversion of ∼100%, N 2 selectivity above 90% at a temperature ∼140 °C. The characterization results, such as BET, XRD, H 2 -TPR, O 2 /NH 3 -TPD and XPS, indicated that this nano-cup structure catalyst possesses high concentration and dispersion of Mn 4+ active species, strong chemisorbed O - or O 2 2- species and highly stable MnO X active components over the annular structures of the TiO 2 shell and SiO 2 sphere, and thus enhanced the low-temperature SCR performance.
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