Doping effect of rare earth metal ions Sm3+, Nd3+ and Ce4+ on denitration performance of MnO catalyst in low temperature NH3-SCR reaction

Optimization of Robust FeMnSmOx Catalyst for Low-Temperature (<150 °C) NH3–SCR of NOx

“…The average oxidation state (AOS) of the FeMnSm-X was calculated based on the double-peak spacing of Mn 3s XPS (Δ E s ). , As listed in Table , it was found that FeMnSm-500 exhibited lower AOS than MnO x , FeMnO y , and FeMnSm-300/400/600. As reported previously, lower AOS (AOS = 8.956–1.126 Δ E s ) of Mn sites is always related to the better low-temperature NH 3 –SCR activity. − The chemical states of Sm species were also analyzed based on Sm 3d XPS (Figure d). It could be found that more Sm 2+ species were formed on FeMnSm-500, which could further facilitate the electronic interaction between different ions (i.e., Fe 3+ + Sm 2+ ↔ Fe 2+ + Sm 3+ , Mn 4+ + Sm 2+ ↔ Mn 2+/3+ + Sm 3+ ).…”

Enhancing effect of Cu and Sn doping on low-temperature catalytic activity and operating temperature window of γ-Fe2O3 in NH3-SCR of NOx

“…For γ-Fe 2 O 3 , several adsorption bands are detected after pretreatment with NO + O 2 at 240 °C for 1 h. The bands at 1602 cm −1 and 1427 cm −1 are ascribed to the adsorbed NO 2 and monodentate nitrate, respectively, while the bidentate nitrate is observed at 1582 and 1300 cm −1 . 9,30,52–55 With the NH 3 passing, the adsorbed NO 2 and bidentate nitrate band intensity steadily declines except for the band of monodentate nitrate. Meanwhile, there are no signals of ad-NH 3 species are seen throughout the test.…”