Cross-flow, filter-sorbent-catalyst for particulate, SO{sub 2} and NO{sub x} control. Final report

Benedek, K.R.; Flytzani‐Stephanopoulos, Maria

doi:10.2172/10190762

Cited by 2 publications

(1 citation statement)

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“…9(b). Benedek and Flytzani-Stephanopoulos [64] have reported an enhancement of the sulfation of ceria by the addition of copper in simulated¯ue gas streams (containing both SO 2 and O 2 ). The enhanced uptake of SO 2 is attributed to the higher oxygen supply induced by copper, since surface oxygen species are active sites for SO 2 adsorption.…”

Section: So 2 Reduction By Chmentioning

confidence: 99%

Redox chemistry over CeO2-based catalysts: SO2 reduction by CO or CH4

et al. 1999

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The catalytic reduction of SO 2 to elemental sulfur by CO and CH 4 over Cu-modi®ed ceria catalysts is studied in this work. Doped and undoped ceria are active catalysts for the SO 2 reduction by CO or CH 4 in the temperature range 450±7508C. When CO is used as the reductant, the reaction follows the redox mechanism, and formation of surface defects (oxygen vacancies) and ceria reducibility are important for catalyst activity. SO 2 strongly adsorbs on the catalyst surface forming sulfates. Partial reduction of sulfate by CO is necessary for the reaction to light off and proceed at low temperatures. Addition of copper improves the low-temperature catalyst activity by increasing the reducibility of ceria and providing sites for CO adsorption. On the other hand, methane activation is limited by the thermal stability of surface sulfates. The activation of methane may involve surface oxygen species and partially reduced metal oxide sites at high temperature. Two independent reactions are proposed and used to explain the catalytic performance of ceria-based oxides in CH 4 SO 2 gas mixtures. One reaction leads to elemental sulfur and complete oxidation (CO 2 H 2 O) products, while the second produces H 2 S and COH 2 O under fuel-rich conditions. The addition of copper suppresses the latter, thus increasing the catalyst selectivity to elemental sulfur. The catalyst activity/selectivity studies were complemented by SO 2 uptake experiments in a TGA and reduction studies of the asprepared and pre-sulfated catalysts in CO and methane, both isothermally and in the TPR mode. #

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Section: So 2 Reduction By Chmentioning

confidence: 99%