前驱体溶液pH值对V2O5-WO3/TiO2催化剂的低温NH3-SCR性能的影响

采用调节前驱体溶液pH值的方法制备了用于低温NH₃-SCR的V₂O₅-WO₃/TiO₂催化剂。通过XPS、Raman光谱、H₂-TPR、NH₃-TPD、NH₃-DRIFT、XRD及物理吸附等手段对催化剂进行了表征分析,并对其脱硝催化活性进行了测试。结果表明,前驱体溶液酸性的增强能够提高催化剂表面聚合态钒物种和V⁴⁺⁽³⁺⁾/V⁵⁺的比值以及表面酸性,增加活性位数量、降低反应的活化能、提高其脱硝催化性能。因此,通过提高前驱体溶液的酸性,有助于制备出脱硝活性较好的NH₃-SCR催化剂。

Effect of the pH value of precursor solution on the catalytic performance of V2O5-WO3/TiO2 in the low temperature NH3-SCR of NOx

V₂O₅-WO₃/TiO₂ catalyst for the selective catalytic reduction of NO_x with NH₃ (NH₃-SCR) was prepared through wet impregnation and characterized by XPS, Raman spectra, H₂-TPR, NH₃-TPD, NH₃-DRIFT, XRD and physical adsorption. The effect of the pH value of vanadium precursor solution on the catalytic performance of V₂O₅-WO₃/TiO₂ in the low temperature NH₃-SCR of NO_x was investigated to optimize the preparation conditions. The results indicated that with the enhancement of precursor solution acidity, more polymeric vanadium species are formed on the catalyst surface; meanwhile, the ratio of V⁴⁺⁽³⁺⁾/V⁵⁺, surface acidity, and quantity of active sites are increased, whereas the de-NO_x performance of the V₂O₅-WO₃/TiO₂ catalyst is largely improved. As a result, a V₂O₅-WO₃/TiO₂ catalyst with high performance in de-NO_x through NH₃-SCR can be obtained by enhancing the precursor solution acidity in the preparation process.