双金属Cu-Ce/SAPO-34催化剂的制备及其NH_(3)-SCR脱硝性能研究

Study on preparation and denitrification performance of NH_(3)-SCR of bimetallic Cu-Ce/SAPO-34 catalyst

采用浸渍法制备了Cu-Ce双金属系列分子筛催化剂(Cu-Ce/SAPO-34),在催化剂评价装置上考察了不同质量比Cu/Ce的分子筛催化剂选择性催化还原NO的性能。通过XRD、SEM、NH_(3)-TPD、XPS、in-situ DRIFTS等多种表征手段对催化剂的结构及微观特性进行了分析。结果表明,改性后Cu-Ce/SAPO-34催化剂脱硝性能良好,具有较宽的活性温度窗口,当Cu、Ce的含量均为4%时,分子筛催化剂脱硝效率最好,在325-500℃脱硝效率均在80%,在400-500℃时,脱硝效率达到了99%以上。双金属Cu-Ce氧化物物种高度分散于催化剂表面,SAPO-34的晶体结构未受影响,且活性物质和载体之间产生较好的相互作用。4Cu-4Ce/SAPO-34具有适量的酸性位点,该配比对催化剂的脱硝性能和稳定性具有积极作用,在NH_(3)-SCR反应过程中遵循E-R机理。

A series of Cu-Ce/SAPO-34 bimetallic zeolite catalysts were prepared by impregnation method.The performance of the different quality Cu/Ce ratios zeolite catalysts for selective catalytic reduction of NO was investigated in a catalyst evaluation device.XRD,SEM,NH_(3)-TPD,XPS,and in-situ DRIFTS were used to characterize and analyze the catalysts.The results show that the modified Cu-Ce/SAPO-34 catalyst has good denitration performance and wide activity temperature window.When the content of Cu and Ce is 4%,the zeolite catalyst has the best denitration efficiency;the denitration efficiency is 80% at 325-500 ℃,and the NO conversion rate is more than 99% at 400-500 ℃.The bimetallic oxide species are highly dispersed on the surface of the catalyst,the crystal structure of SAPO-34 is not affected,and the interaction between the active substance and the support is good.4Cu-4Ce/SAPO-34 has an appropriate amount of acidic sites,and this mixture has positive effects on the denitrification performance and stability of the catalyst.It follows the E-R mechanism in the NH_(3)-SCR reaction process.