CuO, CeO₂ Modified Mg–Al Spinel for Removal of SO₂ from Fluid Catalytic Cracking Flue Gas

Abstract

A Mg-rich Mg–Al spinel modified with CuO and CeO2 via a cogelling method was used to remove SO2 from fluid catalytic cracking (FCC) flue gas. It was found that the generation of a MgO–CuO solid solution was prevented in the presence of CeO2. So CuO had a better dispersion on the adsorbent surface and showed a better catalytic oxidation activity. At the same time, when CuO was added, oxygen defects were found increased greatly in the lattice of CeO2 by Raman spectra and in situ FTIR spectra analyses. This improved the oxygen adsorption capacity of the catalyst. High catalytic oxidation activity and oxygen adsorption capacity of the catalyst enormously promote oxidation of SO2 to SO3, which is much easier to adsorbed by spinel. The SO2 breakthrough time was doubled when the Mg–Al spinel was modified with both CuO and CeO2.

Syngas Production via Methane Dry Reforming over Ceria–Magnesia Mixed Oxide-Supported Nickel Catalysts

“…The bonds marked u are ascribed to Ce 3d3/2, and those labeled v represent the Ce 3d5/2. The bands labeled v′ and u′ are the characteristics of Ce 3+ , and the other six bands (u‴ and ν″′, u′′ and ν′′, and u and ν) are ascribed to Ce 4+ . , …”

“…The bands labeled v′ and u′ are the characteristics of Ce 3+ , and the other six bands (u‴ and ν″′, u′′ and ν′′, and u and ν) are ascribed to Ce 4+ . 61,62 Moreover, the Ce 3+ /Ce 4+ ratio could be determined from the integral area under the corresponding peaks of (v′ and u′) to (u‴, ν″′, u′′, ν′′, u, and ν) as illustrated in Table 3. 62 Noticeably, the percentage concentration of Ce 3+ increases from 25.68 to 30.57% with increase in CeO 2 from 5 to 15% and then decreases to 28.55% with further increase of CeO 2 to 20%.…”

“…61,62 Moreover, the Ce 3+ /Ce 4+ ratio could be determined from the integral area under the corresponding peaks of (v′ and u′) to (u‴, ν″′, u′′, ν′′, u, and ν) as illustrated in Table 3. 62 Noticeably, the percentage concentration of Ce 3+ increases from 25.68 to 30.57% with increase in CeO 2 from 5 to 15% and then decreases to 28.55% with further increase of CeO 2 to 20%. The presence of Ce 3+ can cause charge imbalance, resulting in the generation of oxygen vacancies via the shift from Ce 3+ to Ce 4+ , which increases the amount of oxygen.…”

Construction of cerium-based oxide catalysts with abundant defects/vacancies and their application to catalytic elimination of air pollutants

“…The good deSO x performance was attributable to the synergistic effect between the two oxides: the higher dispersion of the CeO 2 particles was favored by the presence of copper and by some interactive electron transfers between cerium and copper. Pi et al 215 investigated the deSO x performance of magnesium-rich Mg–Al spinel modified with CuO and CeO 2 . The deSO x performances of several samples are shown in Fig.…”