Na对CuSO_(4)/TiO_(2)脱硝催化剂的活性影响研究

Effect of Na on the activity of CuSO_(4)/TiO_(2) deNO_(x) catalysts

Na是燃煤电厂等固定源烟气中常见的元素,可以引起商业钒基脱硝催化剂的失活。目前缺乏关于Na对CuSO_(4)/TiO_(2)脱硝催化剂的影响研究,阻碍了该催化剂的进一步应用。采用湿式浸渍法制备了负载Na的CuSO_(4)/TiO_(2)脱硝催化剂,以研究Na对催化剂活性的影响。使用N2吸附-脱附、XRD、XPS、NH_(3)-TPD和in situ DRIFTS等技术对样品进行了表征。Na会破坏催化剂表面的酸性位并引起吸附氧物种和比表面积的下降,导致CuSO_(4)/TiO_(2)脱硝催化剂的失活。Na含量为2.0%的催化剂其最高NO_(x)转化率由95.2%降至90.1%,并且温度窗口也明显变窄。此外,通过与商业钒基脱硝催化剂的比较,由于CuSO_(4)/TiO_(2)催化剂上具有丰富的酸性位特别是Br?nsted酸性位和吸附氧物种,CuSO_(4)/TiO_(2)脱硝催化剂对Na的抵抗能力显著高于商业钒基催化剂。

Na,which was a common element in the flue gas from stationary sources like coal-fired power plants,could cause the deactivation of commercial V-based deNO_(x) catalysts.The research about the effect of Na on CuSO_(4)/TiO_(2) deNO_(x) catalysts was still absent,which hindered the further application of the catalyst.To investigate the effect of Na on the activity of CuSO_(4)/TiO_(2) deNO_(x) catalysts,a series of CuSO_(4)/TiO_(2) with different Na contents were prepared by wet-impregnation method.N2 adsorptiondesorption,XRD,XPS,NH_(3)-TPD,and in situ DRIFTS were used to characterize the sample.Na would poison the surface acid sites of the catalyst and lead to the decrease of adsorbed oxygen species and specific surface area,causing the deactivation of CuSO_(4)/TiO_(2) catalysts.The highest NO_(x) conversion decreased from 95.2% to 90.1% after 2.0% Na was loaded on the catalyst.In addition,due to the abundant acid sites especially Bronsted acid sites and adsorbed oxygen species,CuSO_(4)/TiO_(2) catalyst exhibited a higher Na resistance than commercial catalysts.