燃煤烟气中砷对V_2O_5-WO_3/TiO_2 SCR脱硝催化剂性能的影响

通过将商业V_2O_5-WO_3/TiO_2脱硝催化剂暴露于含As_2O_3烟气中,制备了砷中毒催化剂,并运用X射线衍射(XRD)、比表面积(BET)、NH3化学吸附、傅里叶变换红外光谱(FT-IR)、X射线光电子能谱等技术表征分析了砷对催化剂性能的影响,并提出了催化剂砷中毒机理。结果表明,砷对催化剂具有严重的毒害作用,As_2O_3会吸附在催化剂表面,并被催化剂氧化形成As_2O_5覆盖层,减小催化剂比表面积,减少催化剂V活性位,阻止催化剂对NH3的吸附,造成催化剂失活。

Influence of arsenic in flue gas on the performance of V2O5-WO3/TiO2 catalyst in selective catalytic reduction of NOx

The effect of arsenic on the performance of commercial V₂O₅-WO₃/TiO₂ catalyst for selective catalytic reduction (SCR) of NO_x was investigated with the assistance of XRD, N₂ sorption, NH₃ chemisorption, FT-IR and XPS; an arsenic poisoning mechanism was proposed. The results illustrated that As₂O₃ in flue gas is a serious toxicant to the V₂O₅-WO₃/TiO₂ catalyst. As₂O₃ adsorbed on the catalyst are mostly oxidized to As₂O₅, which covers the catalyst surface and results in a decrease of surface area and active V sites; as a result, the adsorption of NH₃ is then inhibited, which leads to the deactivation of the V₂O₅-WO₃/TiO₂ catalyst for SCR.