title: Novel Effective Catalyst for Elemental Mercury Removal from Coal-Fired Flue Gas and the Mechanism Investigation.
abstract: Mercury pollution from coal-fired power plants has drawn attention worldwide. To achieve efficient catalytic oxidation of Hg(0) at both high and low temperatures, we prepared and tested novel IrO2 modified Ce-Zr solid solution catalysts under various conditions. It was found that the IrO2/Ce0.6Zr0.4O2 catalyst, which was prepared using the polyvinylpyrrolidone-assisted sol-gel method, displayed significantly higher catalytic activity for Hg(0) oxidation. The mechanism of Hg(0) removal over IrO2/Ce0.6Zr0.4O2 was studied using various methods, and the Hg(0) oxidation reaction was found to follow two possible pathways. For the new chemisorption-regeneration mechanism proposed in this study, the adsorbed Hg(0) was first oxidized with surface chemisorbed oxygen species to form HgO; the HgO could desorb from the surface of catalysts by itself or react with adsorbed HCl to be release in the form of gaseous HgCl2. O2 is indispensable for the chemisorption process, and the doping of IrO2 could facilitate the chemisorption process. In addition, the Deacon reaction mechanism was also feasible for Hg(0) oxidation: this reaction would involve first oxidizing the adsorbed HCl to active Cl species, after which the Hg(0) could react with Cl to form HgCl2. Additionally, doping IrO2 could significantly improve the Cl yield process. In summary, the novel IrO2 modified catalyst displayed excellent catalytic activity for elemental mercury oxidation, and the proposed reaction mechanisms were determined reasonably.
authors.affiliation: School of Environmental Science and Engineering, Shanghai Jiao Tong University , 800 Dong Chuan Road, Shanghai, 200240 PR China.
authors.forename: Wanmiao
authors.initials: W
authors.lastname: Chen
authors.affiliation: School of Environmental Science and Engineering, Shanghai Jiao Tong University , 800 Dong Chuan Road, Shanghai, 200240 PR China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Pei
authors.affiliation: School of Environmental Science and Engineering, Shanghai Jiao Tong University , 800 Dong Chuan Road, Shanghai, 200240 PR China.
authors.forename: Wenjun
authors.initials: W
authors.lastname: Huang
authors.affiliation: School of Environmental Science and Engineering, Shanghai Jiao Tong University , 800 Dong Chuan Road, Shanghai, 200240 PR China.
authors.forename: Zan
authors.initials: Z
authors.lastname: Qu
authors.affiliation: School of Environmental Science and Engineering, Shanghai Jiao Tong University , 800 Dong Chuan Road, Shanghai, 200240 PR China.
authors.forename: Xiaofang
authors.initials: X
authors.lastname: Hu
authors.affiliation: School of Environmental Science and Engineering, Shanghai Jiao Tong University , 800 Dong Chuan Road, Shanghai, 200240 PR China.
authors.forename: Naiqiang
authors.initials: N
authors.lastname: Yan
mesh_terms: D002384:Catalysis; D003031:Coal; D005740:Gases / Q000737:chemistry*; D006859:Hydrogen / Q000737:chemistry; D007495:Iridium / Q000737:chemistry; D008628:Mercury / Q000302:isolation & purification*; D010084:Oxidation-Reduction; D056951:Photoelectron Spectroscopy; D013696:Temperature
chemical_list: D003031:Coal; D005740:Gases; C044458:iridium oxide; D007495:Iridium; D006859:Hydrogen; D008628:Mercury