钾对CuSO_(4)/TiO_(2)脱硝催化剂的失活效应  

Effect of Potassium on the Performance of a CuSO_(4)/TiO_(2) Catalyst Used in the Selective Catalytic Reduction of NO_(x) by NH_(3)

作　　者：于艳科 耿梦荞 魏德胜 何炽[1,2,3] Yanke Yu;Mengqiao Geng;Desheng Wei;Chi He(Department of Environmental Science and Engineering,School of Energy and Power Engineering,Xi'an Jiaotong University,Xi'an 710049,China;State Key Laboratory of Multiphase Flow in Power Engineering,Xi'an Jiaotong University,Xi'an 710049,China;National Engineering Laboratory for VOCs Pollution Control Material&Technology,University of Chinese Academy of Sciences,Beijing 101408,China)

机构地区：[1]西安交通大学能源与动力工程学院环境科学与工程系,西安710049 [2]西安交通大学动力工程多相流国家重点实验室,西安710049 [3]中国科学院大学挥发性有机物污染控制材料与技术国家工程实验室,北京101408

出　　处：《物理化学学报》2023年第4期76-84,共9页Acta Physico-Chimica Sinica

基　　金：国家自然科学基金(21906127,21876139,21922606);中国博士后科学基金(2021M692550);王宽诚教育基金会和西安交通大学分析测试中心资助。

摘　　要：为了减少碳排放,在世界各地兴建了越来越多的生物质电厂。钾元素是生物质电厂烟气中的一种典型元素并且可以引起脱硝催化剂的失活。具有优异抗SO2性能的CuSO_(4)/TiO_(2)催化剂被认为是一种有前景的非钒基脱硝催化剂。但是,钾对CuSO_(4)/TiO_(2)催化剂的影响仍不清楚。本文研究了钾对CuSO_(4)/TiO_(2)催化剂的影响并且与商业V_(2)O_(5)-WO_(3)/TiO_(2)(VWTi)催化剂作了比较,采用多种表征方法对催化剂样品进行了表征。钾可以引起CuSO_(4)/TiO_(2)和VWTi催化剂的失活,但是CuSO_(4)/TiO_(2)催化剂对钾的抵抗能力明显高于商业VWTi催化剂。钾会与CuSO_(4)/TiO_(2)催化剂中的CuSO_(4)发生反应生成CuO和K_(2)SO_(4)。CuO的形成会引起催化剂上NO_(x)转化率和N_(2)选择性的下降。另外,钾还会与催化剂上的BrФnsted酸性位(S-OH)结合从而阻碍NH_(3)在催化剂表面的吸附。再者,高浓度的钾还会引起催化剂比表面积的下降。值得注意的是,丰富的酸性位和表面吸附氧含量应该是CuSO_(4)/TiO_(2)催化剂对钾具有较高抵抗力的原因。本工作的研究结果表明CuSO_(4)/TiO_(2)催化剂是一种适用于生物质电厂烟气脱硝的潜在催化剂。Owing to its renewability,abundance,and low environmental impact,biomass is considered to be a viable eco-friendly fuel.Various biofuel-fired power plants have been built worldwide to reduce carbon emissions.Potassium(K)is a typical impurity in the flue gas from biofuel combustion that can deactivate the catalyst used in the selective catalytic reduction of NO_(x) by ammonia(NH_(3)-SCR).CuSO_(4)/TiO_(2),with excellent sulfur dioxide tolerance,is thought to be a promising vanadium-free catalyst for NH3-SCR;however,the influence of K on the CuSO_(4)/TiO_(2) catalyst is still unknown.Therefore,in this study,the effect of K on the NH3-SCR performance of CuSO_(4)/TiO_(2) were investigated and compared with the effect on the performance of the commercial V_(2)O_(5)-WO_(3)/TiO_(2)(VWTi)catalyst.K-poisoned catalysts were prepared via wet impregnation using potassium acetate as the K source.Nitrogen(N2)adsorption-desorption,X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS),NH3-temperature programmed desorption(NH3-TPD),H_(2)-temperature programmed reduction(H_(2)-TPR),and in situ diffuse reflectance infrared Fourier-transform spectroscopy(in situ DRIFTS)were used to characterize the prepared catalysts.The NO_(x) conversion over CuSO_(4)/TiO_(2) with 1.0%(w)K was 92.1%(at 350℃),which was higher than the conversion(75.1%)achieved over the commercial VWTi catalyst with the same K content.The XRD,XPS,and H_(2)-TPR results suggested that K reacted with the CuSO_(4) in the CuSO_(4)/TiO_(2) catalyst to form CuO and K_(2)SO_(4).The presence of CuO enhanced the oxidation of NH3 to N2O,NO,and NO2 during NH3-SCR,thereby decreasing the NO_(x) conversion and N2 selectivity over CuSO_(4)/TiO_(2).Moreover,based on the results from NH3-TPD and in situ DRIFTS of NH3 adsorption,it can be concluded that the Brønsted acid sites(S-OH)were poisoned by K,which restrained the adsorption of NH_(3) on CuSO_(4)/TiO_(2).Additionally,the high K content altered the pore structure of the catalyst,leading to a decrease in the specific surf

关 键 词：NH_(3)-SCR催化剂 氮氧化物 BrФnsted酸性位 氧化铜 生物质电厂 

分 类 号：O643[理学—物理化学]