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Enhanced activity and SO 2 resistance of Co‐modified CeO 2 ‐TiO 2 catalyst prepared by facile co‐precipitation for elemental mercury removal in flue gas
Author(s) -
Li Honghu,
Zhang Jingdong,
Cao Yanxiao,
Li Fei,
Liu Chaoyang,
Song Yongwei,
Hu Jiangjun,
Wang Yuan
Publication year - 2020
Publication title -
applied organometallic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.53
H-Index - 71
eISSN - 1099-0739
pISSN - 0268-2605
DOI - 10.1002/aoc.5463
Subject(s) - chemistry , catalysis , flue gas , oxygen storage , x ray photoelectron spectroscopy , inorganic chemistry , oxygen , redox , adsorption , nuclear chemistry , chemical engineering , organic chemistry , engineering
The Co‐modified CeO 2 ‐TiO 2 catalyst prepared by facile co‐precipitation was used for efficient elemental mercury oxidation in flue gas. Results indicated that Co doping greatly enhanced the activity and SO 2 resistance of the CeO 2 ‐TiO 2 catalyst. In the presence of 5% O 2 , 500 ppm NO, 800 ppm SO 2 and 3% H 2 O at 200 °C, the Hg 0 removal efficiency of CeCo 3 /Ti could maintain at about 87% for a relatively long time. Characterizations of catalysts (BET, XRD, Raman spectroscopy, TEM, H 2 ‐TPR, O 2 ‐TPD, XPS, TG‐MS and SO 2 ‐DRIFTS) were carried out to reveal the mechanism of Co modification on the redox ability, SO 2 resistance and resultant mercury oxidation removal performance of catalyst. It was found that an interaction of Ce with Co promoted the dispersion of CeO 2 , increased chemisorbed oxygen concentration, and improved the oxygen storage capacity and the reducibility of catalyst, which was beneficial to the improvement of Hg 0 oxidation removal. Hg 0 would adsorb onto the catalyst and react with surface active oxygen species replenished by gas‐phase O 2 to be oxidized via Mars‐Maessen mechanism. SO 2 consumed the surface active oxygen species and resulted in the reduction of Ce 4+ to Ce 3+ , which induced the deactivation of catalyst. The introduced Co in CeO 2 ‐TiO 2 catalyst exerted the function of protecting Ce 4+ from being poisoned by SO 2 and thus promoted the sulfur resistance and Hg 0 removal performance of the catalyst in the presence of SO 2 .