Study on preparation and denitrification performance of NH3-SCR of bimetallic Cu-Ce/SAPO-34 catalyst
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摘要: 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、NH3-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NH3-SCR反应过程中遵循E-R机理。Abstract: 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, NH3-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 NH3-SCR reaction process.
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Key words:
- denitration /
- SAPO-34 /
- NH3-SCR /
- catalyst /
- active temperature
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图 1 不同Cu/Ce质量比催化剂的脱硝效率
Figure 1 NO conversion of catalysts with different Cu/Ce mass ratios
图 2 不同Cu/Ce质量比催化剂的XRD谱图
Figure 2 XRD patterns of catalysts with different Cu/Ce mass ratios
图 3 不同Cu/Ce质量比催化剂的SEM照片（倍数分别为10000、1000倍）
Figure 3 SEM images of different Cu/Ce mass ratios (the multiples are 10000 and 1000 respectively)
图 4 不同Cu/Ce质量比催化剂的NH3-TPD谱图
Figure 4 NH3-TPD spectra of catalysts with different Cu/Ce mass ratios
图 6 4Cu-4Ce/SAPO-34催化剂表面NH3吸附in-situ DRIFTS谱图
Figure 6 In-situ DRIFTS of NH3 adsorbed over the 4Cu-4Ce/SAPO-34 catalyst
图 7 4Cu-4Ce/SAPO-34催化剂表面NH3吸附饱和后通入NO+O2 in-situ DRIFTS谱图
Figure 7 In-situ DRIFTS of NO+O2 reacting with pre-adsorbed NH3 over the 4Cu-4Ce/SAPO-34 catalyst
图 8 4Cu-4Ce/SAPO-34催化剂表面NO+O2吸附in-situ DRIFTS谱图
Figure 8 In-situ DRIFTS of NO+O2 adsorbed over the 4Cu-4Ce/SAPO-34 catalyst
图 9 4Cu-4Ce/SAPO-34催化剂表面NO+O2吸附饱和后通入NH3 in-situ DRIFTS谱图
Figure 9 In-situ DRIFTS of NH3 reacting with pre-adsorbed NO+O2 over the 4Cu-4Ce/SAPO-34 catalyst
表 1 不同价态金属离子的特征峰面积
Table 1 Characteristic peak areas of metal ions with different valence states
Catalyst Cu+ Cu2+ Ce3+ Ce4+ 4Cu/SAPO-34 7966.6 4387.3 − − 4Cu-4Ce/SAPO-34 5345.6 7127.3 105753 41376.7 4Ce/SAPO-34 − − 91606.2 51107.9 
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