SO2对Zr掺杂Mn-Ce/GR催化剂低温脱硝性能的影响

通过水热法分别制备掺杂Zr、Sb、Sn和Si的Mn-Ce/石墨烯（Mn-Ce/GR）催化剂，考察了其在低温氨气选择性催化还原（NH3-SCR）过程中对NOx的去除效率和抗SO2中毒性能。结果显示，掺杂Zr后，催化剂具有良好的低温脱硝活性，在120 ℃时，其NOx转化率和N2选择性分别达到97.26%和98.97%，且当进气中SO2的体积分数为200×10-6时，其抗硫性明显优于掺杂其他3种元素的催化剂，原因是硫酸盐在掺杂Zr催化剂表面的沉积速率有所减缓。通过Raman、XRD、HRTEM、SEM、BET、XPS、FT-IR、H2-TPR以及NH3-TPD等表征手段对掺杂Zr的Mn-Ce/GR新鲜催化剂和失活样品进行表征分析。发现，SO2对掺杂Zr催化剂的毒化作用主要有4个方面：Oα大量减少，还原能力减弱；活性组分CeO2含量减少，储氧能力减弱；催化剂表面Zr含量减少，酸性位点减少；硫酸盐和硝酸盐在催化剂表面大量沉积，减少了催化剂的比表面积。

Effect of SO2 on de-NOx performance of Zr doping Mn-Ce/GR catalyst at low temperature

Zr, Sb, Sn and Si were used to modify the Mn-Ce/graphene(Mn-Ce/GR) catalyst, respectively. SO2 resistance of these catalysts prepared by hydrothermal method for low-temperature selective catalytic reduction(SCR) of NOx with NH3 was investigated in this study. The results indicated that Zr doping Mn-Ce/GR catalyst showed superior activity. NOx conversion and N2 selectivity were 97.26% and 98.97%, respectively at 120 °C. And it had higher SO2 resistance than the others when SO2 with a volume fraction of 200×10-6 was fed in. One possible reason was that the deposition rate of sulfates reduced. The fresh and deactivated Zr doping Mn-Ce/GR catalysts were characterized by Raman spectroscopy, XRD, HRTEM, SEM, BET, XPS, FT-IR, H2-TPR and NH3-TPD. The characterized results indicated that the deactivation of Zr doping catalysts was mainly caused by the four reasons. Firstly, the decrease of Oα concentration on the surface weakened the reduction ability. Secondly, the decrease of CeO2 content led the reduction of oxygen storage capacity. Thirdly, with the decrease of Zr content on catalysts surface, the acid sites were reduced. Finally, the deposion of sulfates and nitrates decreasedthe specific surface area of the catalysts.