Direct Decomposition of NO into N2 and O2 on SrFe0.7Mg0.3O3 Perovskite Oxide

Abstract

NO direct decomposition on doped SrFeO3 perovskite oxide was investigated. The ability of SrFeO3 for direct decomposition of NO is strongly affected by the dopant in Fe sites. Among the examined dopants and compositions, the highest yield of N2 was achieved on SrFe0.7Mg0.3O3. When SrFe0.7Mg0.3O3 was loaded with Pt, the N2 yield further improved, and the light-off temperature fell by 100 K. On this catalyst, the yields of N2 and O2 were 56 and 35%, respectively, at 1123 K. On the Pt-loaded SrFe0.7Mg0.3O3 catalyst, the NO decomposition rate increased with increase in the NO partial pressure with PNO1.31. The presence of oxygen slightly decreased the N2 yield with PO2−0.12. Therefore, the effect of oxygen poisoning on NO decomposition upon Pt-loaded SrFe0.7Mg0.3O3 is small. From the result of O2-TPD, Pt loading possibly weakens the adsorption strength of surface oxygen and enhances NO adsorption. In summary, this study shows that the substitution of Fe with lower valence cation in SrFeO3 and also loading a small amount of Pt are highly effective for increasing the NO decomposition activity.

Recent progress in catalytic NO decomposition

“…XPS and molecular orbital calculations suggested that the instability of the [41] were also reported. Ishihara and co-workers [42,43] studied the effect of B-site substitution on the activity of SrFe 0.7 M 0.3 O 3 and BaMn 0.8 M 0.2 O 3 (M: Mg, Si, Ti, Cr, Mn, Fe, Co, Ni, Cu, Ga, Ge, Zr, Ru, Sn, Ce, Ta, and Ir), and found that the substitution with Mg, Zr, Sn, Ni, Co and so on in both catalysts is effective in promoting NO decomposition, while that with Cr and Cu was not effective. They explained the positive effect of B-site substitution with Mg by the acceleration of O 2 desorption.…”

Advanced materials for environmental catalysts

“…A number of materials have been reported as active catalysts for direct NO decomposition, such as zeolites,36 noble metals,37 perovskites,38–42 and other mixed or complex oxides 43–51. However, several problems remain unsolved, which prevent the practical application of such catalysts under exhaust conditions.…”

“…2), similar to δ‐type cubic Bi 2 O 3 described earlier. The metal atoms are six coordinates in the C‐type cubic rare earth oxides,50 which can be produced from the fluorite‐type dioxide (eight‐coordinate one) when one‐fourth of the oxygen atoms of this network are removed (Fig. 2).…”

Direct Decomposition of NO into N<sub>2</sub> and O<sub>2</sub> Over C-type Cubic Y<sub>2</sub>O<sub>3</sub>-Tb<sub>4</sub>O<sub>7</sub>-ZrO<sub>2</sub>

“…In contrast to the above processes employing ammonia or urea, direct catalytic decomposition of NO into N 2 and O 2 (2NO → N 2 + O 2 ) is the most ideal route for NO x removal, because no reducing agents and no special equipment are required. A number of materials, such as zeolites [2,3], perovskites [4][5][6], and other complex oxides [7][8][9][10][11][12][13][14][15][16][17][18], have been proposed as active catalysts for direct NO decomposition. However, the NO decomposition activity of these conventional catalysts is significantly decreased in the presence of O 2 and CO 2 , due to strong adsorption of these molecules on the surface of the catalysts.…”