Sm3+掺入对MnO2/TiO2催化剂低温脱硝性能的影响

摘要

A series MnO2/Ti O2catalysts (Sm-Mn/Ti) were modified with Sm3+using a extrusion method.The effect of Sm3+on the catalytic performance of the MnO2/Ti O2during selective catalytic reduction (SCR) of NOxwas investigated.Several tests were carried out to characterize the catalysts, such as the X-ray diffraction, nitrogen adsorption and desorption, visible Raman spectrum and scanning electron microscope, respectively.Results showed that the additions of Sm3+could inhibit the growth of Ti O2particles, which increased the specific surface areas and the defects species concentration.It was beneficial for the adsorption of reaction gas and the enhancement of catalytic activity.Therefore, the appropriate addition of Sm3+improved catalytic activity at the low temperature, the resistance to sulphur poisoning, and the resistance to alkali poisoning.It also broadened the active temperature window while the amount was appropriate.Under the GHSV of 5 000 h-1, the 4％Sm-Mn/Ti obtained the maximum activity (99％) at195℃and 86％NO conversion at 115℃.%采用挤出成型法制备Sm3+掺杂MnO2/Ti O2催化剂(Sm-Mn/Ti),研究Sm3+掺入对MnO2/Ti O2催化剂低温脱硝性能的影响,采用X射线衍射、氮气吸附脱附、可见光拉曼光谱以及扫描电子显微镜等对催化剂进行表征.结果表明,Sm3+的掺入抑制了Ti O2的颗粒长大,不仅增大了催化剂的比表面积,同时提高MnO2/Ti O2催化剂的缺陷浓度,有利于催化剂表面反应气体的吸附以及催化反应的进行.因此,适量Sm3+掺入会明显提升MnO2/Ti O2催化剂的低温脱硝活性、抗硫中毒、抗碱金属中毒能力,拓宽其活性温度窗口.5 000 h-1条件下,4％Sm-Mn/Ti催化剂在195℃达到最高脱硝率99％,并且在115℃脱硝率达到86％.