采用超声波增强的浸渍法合成了CeO_2-TiO_2催化剂,并采用BET,XRD,XPS等分析手段对催化剂进行了表征。利用固定床反应器,在模拟燃煤烟气条件下研究了CeO_2-TiO_2催化剂对单质汞的催化氧化行为及机理。结果表明：CeO_2-TiO_2催化剂在低温范围（150～250°）具有很强的催化氧化汞的能力;最佳的CeO_2/TiO_2质量比在1.5左右,此时汞的氧化效率可高达90%以上;P25,Evonik TiO_2比锐钛矿TiO_2更适合做铈基催化剂载体;CeO_2-TiO_2催化剂上汞的催化氧化符合Langmuir-Hinshelwood机理,即吸附态的汞与其邻近的活性物质反应生成氧化态汞。
An ultrasonic-assisted impregnation method were employed to synthesize CeO_2-TiO_2 （CeTi）catalysts for oxidizing elemental mercury（Hg~0）in flue gas.The catalysts were characterized by BET surface area analysis,X-ray diffraction（XRD）measurement and X-ray photoelectron spectroscopy（XPS）analysis.Mercury oxidation performance and mechanism over CeTi catalysts were studied under simulated coal combustion flue gas using a fixed bed reactor.The CeTi catalysts exhibited high Hg~0 oxidation activity at temperatures ranging from 150 to 250℃.The optimal CeO_2/TiO_2 weight ratio was 1.5,where Hg~0 oxidation efficiency was higher than 90%.Compare to anatase TiO_2,P25,Evonik TiO_2 was more suitable to be the support of CeTi catalysts.Hg~0 oxidation over CeTi catalysts was proposed to follow the Langmuir-Hinshelwood mechanism whereby adsorbed Hg°reacts with adjacent active species to form oxidized mercury.
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