CuO-WO3/TiO2催化剂制备方法对NH3-SCR脱硝性能的影响

分别采用溶胶-凝胶法和浸渍法制备xCuO-yWO₃/TiO₂催化剂(x,y分别代表样品中ω(CuO)和ω(WO₃)),并在微型固定床反应器中对制备的xCuO-yWO₃/TiO₂催化剂进行选择性催化还原脱硝(NH₃-SCR)性能评价。结果表明:采用溶胶-凝胶法制备的2CuO-6WO₃/TiO₂催化剂具有较好的脱硝性能,在250~350 ℃,NO_x转化率达到90%以上,相较于浸渍法制备的2CuO-6WO₃/TiO₂催化剂活性明显提高。并采用BET、XRD、H₂-TPR、NH₃-TPD和XPS等表征手段对制备的催化剂进一步表征分析,结果表明:通过溶胶-凝胶法制备2CuO-6WO₃/TiO₂催化剂的比表面积和表面化学吸附氧明显提高,且还原能力和酸性增强,对NH₃的吸附能力亦有所提高,因此溶胶-凝胶法制备的2CuO-6WO₃/TiO₂催化剂表现出较好的NH₃-SCR脱硝性能。

EFFECT OF PREPARATION METHODS OF CuO-WO3/TiO2 CATALYSTS ON NH3-SCR DENITRATION ACTIVITY

xCuO-yWO₃/TiO₂ catalysts (x and y represent the mass fraction of CuO and WO₃ in the sample, respectively) were prepared by sol-gel method and impregnation method, respectively, and the SCR denitration performance (NH₃-SCR) of the catalysts was evaluated in a miniature fixed-bed quartz reactor. It was found that the 2CuO-6WO₃/TiO₂ catalyst by the sol-gel method had good denitration performance, and made NO_x conversion rate over 90% in temperature range of 250~350 ℃, which activity was improved significantly compared with 2CuO-6WO₃/TiO₂ catalyst by impregnation method. The prepared catalysts were characterized by BET, XRD, H₂-TPR, NH₃-TPD and XPS. The results showed that for the 2CuO-6WO₃/TiO₂ catalyst prepared by sol-gel method, the specific surface area, the surface adsorbed oxygen, the redox potential and adsorption capacity of NH₃ increased significantly than the catalyst prepared by the impregnation method. Therefore, the 2CuO-6WO₃/TiO₂ catalyst prepared by sol-gel method exhibited excellent NH₃-SCR activity and high N₂ selectivity.