铁钨复合氧化物用于NH_3选择性催化还原NO

Iron-Tungsten Mixed Oxide Catalyst for the Selective Catalytic Reduction of NO with NH_3

采用共沉淀法制备铁钨复合氧化物催化剂,用于NH3选择性催化还原NO,考察了Fe/W物质的量之比、反应空速、SO2和H2O对催化剂脱硝活性的影响,同时运用SEM、XRD、BET、NH3-TPD等表征手段对催化剂的微观形貌、晶型、比表面积、孔结构参数及表面酸性进行了分析。实验结果表明当n（Fe）∶n（W）=4∶1时,催化剂的反应活性最佳,其在300~400℃温度范围内及GHSV=75 000 h-1条件下NO转化率仍保持在90%以上,同时其也显示出较强的抗SO2和H2O中毒性能。通过表征发现Fe与W之间强烈的相互作用,较大的比表面积和催化剂较强的酸性是催化剂催化活性较好的主要原因。

Iron-Tungsten mixed oxide catalyst was prepared by the co-precipitation method and used for the selective catalytic reduction of NO with NH3. The effects of molar ratios of Fe / W,space velocity,SO2 and H2O on the NO conversion were investigated. The characterization means of SEM,XRD,BET and NH3-TPD were also applied to analyze the physicochemical properties of the catalyst. Among all the irontungsten mixed oxides,the catalyst with the Fe / W molar ratio of 4∶ 1 exhibited the best catalytic activity with above 90% NO conversion in the temperature range from 300 ℃ to 400 ℃ under the space velocity of 75 000 h- 1. The Fe4 WOxcatalyst also showed high tolerance to SO2 and H2O in the test condition.The characterization result showed that the strong interaction between Fe and W,the large specific surface,and the strong acidity were the main reasons for the iron-tungsten mixed oxide catalyst to acquire the high catalytic activity.