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《环境科学与工程前沿(英文)》 >> 2013年 第7卷 第3期 doi: 10.1007/s11783-013-0489-0

Chemical deactivation of V

1. State Key Laboratory of New Ceramics & Fine Process, Department of Materials Science and Engineering, Tsinghua University, Beijing 100084, China; 2. Advanced Materials Institute, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, China; 3. Yangtze Delta Region Institute of Tsinghua University, Jiaxing 314000, China

发布日期: 2013-06-01

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摘要

V O -WO /TiO catalyst was poisoned by impregnation with NH Cl, KOH and KCl solution, respectively. The catalysts were characterized by X-ray diffraction (XRD), inductively coupled plasma (ICP), N physisorption, Raman, UV-vis, NH adsorption, temperature-programmed reduction of hydrogen (H -TPR), temperature-programmed oxidation of ammonia (NH -TPO) and selective catalytic reduction of NO with ammonia (NH -SCR). The deactivation effects of poisoning agents follow the sequence of KCl>KOH>>NH Cl. The addition of ammonia chloride enlarges the pore size of the titania support, and promotes the formation of highly dispersed V=O vanadyl which improves the oxidation of ammonia and the high-temperature SCR activity. K ions are suggested to interact with vanadium and tungsten species chemically, resulting in a poor redox property of catalyst. More importantly, potassium can reduce the Br?nsted acidity of catalysts and decrease the stability of Br?nsted acid sites significantly. The more severe deactivation of the KCl-treated catalyst can be mainly ascribed to the higher amount of potassium resided on catalyst.

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