Abstract Lead (Pb) species are inescapable constituents of the flue gas from coal-fired power plants and other thermal devices, which can cause impeding effects on the selective catalytic reduction (SCR) reactions. Here, the poisoning effects of Pb on the V2O5-MoO3/TiO2 type SCR catalyst were examined. The poisoned catalysts were prepared by the solid diffusion and incipient wetness impregnation (IWI) methods. The catalytic activity tests indicated that the Pb-doped catalyst prepared by the IWI method suffered a considerable drop in catalytic activity, while a slender influence was observed on the Pb-loaded catalysts prepared by solid diffusion method. Comprehensive characterizations and density functional theory (DFT) calculations were performed on the fresh and poisoned catalysts prepared by the IWI method to unveil the deactivation mechanism. The results showed that Pb species covered the active sites (V species) on the catalyst surface, resulted in the decrease in chemisorbed oxygen, hence reducing the surface acidities. The decrease in reducibility of the catalyst was an important factor for poisoning of the catalyst. Moreover, Pb species reacted with MoO3 to form PbMoO4 which agglomerated on the catalyst surface to further deactivate the catalyst.

中文翻译：

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Pb 物种对 V2O5-MoO3/TiO2 催化剂的抑制作用，用于用 NH3 选择性催化还原 NO：DFT 支持的实验研究

摘要 铅 (Pb) 物种是燃煤电厂和其他热力设备烟气中不可避免的成分，会对选择性催化还原 (SCR) 反应造成阻碍。在此，研究了 Pb 对 V2O5-MoO3/TiO2 型 SCR 催化剂的中毒影响。中毒催化剂采用固体扩散法和初湿浸渍法(IWI)制备。催化活性测试表明，IWI法制备的Pb掺杂催化剂的催化活性明显下降，而固体扩散法制备的Pb负载催化剂的催化活性影响较小。对通过 IWI 方法制备的新鲜和中毒催化剂进行综合表征和密度泛函理论 (DFT) 计算，以揭示失活机制。结果表明，Pb 物种覆盖了催化剂表面的活性位点（V 物种），导致化学吸附氧的减少，从而降低了表面酸度。催化剂还原性的降低是催化剂中毒的重要因素。此外，Pb 物种与 MoO3 反应形成 PbMoO4，PbMoO4 聚集在催化剂表面，进一步使催化剂失活。