Investigation of SO₂tolerance of Ce-modified activated semi-coke based catalysts for the NO + CO reaction

Abstract

The SO2tolerance mechanism of Ce-modified activated semi-coke based catalysts for the NO + CO reaction.

Reaction of NO + CO over Ce-Modified Cu–FeOx Catalysts at Low Temperature

“…In Figure a, the two catalysts are sampled from the reaction for SO 2 . The curve of Cu 1 Ce 0.5 Fe 1.5 O 4.25 shows two obvious peaks at 890 and 680 °C, which can be assigned to the decomposition of sulfates and sulfites. , Besides this, in the temperature range 100–400 °C, there is a convex curve; we speculate that this is a desorption signal for the chemisorbed SO 2 . , For Cu 0.5 Ce 0.25 Fe 2.25 O 4.375 , the peak at 890 °C disappears, and the center of the low temperature convex curve shifts to approximately 230 °C. This indicates that sulfates are difficult to form on the surface of Cu 0.5 Ce 0.25 Fe 2.25 O 4.375 ; i.e., a higher percentage of Fe could inhibit the generation of sulfates.…”

“…The curve of Cu 1 Ce 0.5 Fe 1.5 O 4.25 shows two obvious peaks at 890 and 680 °C, which can be assigned to the decomposition of sulfates and sulfites. 49,50 Besides this, in the temperature range 100−400 °C, there is a convex curve; we speculate that this is a desorption signal for the chemisorbed SO 2 . 49,50 For Cu 0.5 Ce 0.25 Fe 2.25 O 4.375 , the peak at 890 °C disappears, and the center of the low temperature convex curve shifts to approximately 230 °C.…”

“…Along with the peak at 910 °C, there is a shoulder at approximately 860 °C. We speculate that the peak at 600 °C is ascribable to the desorption of sulfites coordinated with Cu species, 49,50 the peak at 700 °C is due to sulfites coordinated with Fe species, and the peak at 850 °C is due to sulfates coordinated with Fe. As for the curve of Cu 0.5 Ce 0.25 Fe 2.25 O 4.375 , the two main peaks appear at ∼700 and ∼850 °C; this supports the speculation of the assignment for the curve peak of Cu 1 Ce 0.5 Fe 1.5 O 4.25 .…”

Influence of cerium doping on Cu–Ni/activated carbon low-temperature CO-SCR denitration catalysts

“…Due to the special surface structure of AC, the surface oxygen species could be divided into three components: lattice oxygen (Oβ), surface adsorbed oxygen (Oα) and oxygen species in the hydroxyl group (Oγ). 43 According to previous studies, 41 Oα was derived with a BE of 531.1–530.4 eV from hydroxyl species or from the O 2 2− and O − on a catalyst's surface, which are defective oxides. Also, the Oγ-derived catalyst surface with a BE of 533.5–535.5 eV the adsorbed H 2 O, and the BE of 529.06–530.4 eV usually comes from the lattice oxygen of metal oxides.…”