Fe、Ce掺杂六铝酸盐催化剂制备及脱硝抗硫性能

Preparation of Fe and Ce doped hexaaluminate catalysts and their property of denitrification and sulfur tolerance

用共沉淀法制备六铝酸盐催化剂LaMxAl12-xO19-δ(M=Fe、Ce、FeCe)。用XRD、H2-TPR以及NO转化率对催化剂进行表征和活性验证,分析不同离子取代Al3+对六铝酸盐结构和脱硝抗硫活性的影响。结果表明,Fe离子易于进入六铝酸盐晶格,形成完整的六铝酸盐结构,LaFeAl11O19-δ催化剂具有良好的低温脱硝活性。Ce离子不易进入六铝酸盐晶格,主要以CeO2的形式存在,LaCeAl11O19-δ催化剂有良好的高温脱硝活性。加入SO2后,两种催化剂都有不同程度的失活现象,其中,LaFeAl11O19-δ催化剂失活较为明显。LaFeCeAl10O19-δ催化剂中,Fe离子和Ce离子间会产生协同作用,提高了催化剂的脱硝抗硫活性。

Hexaaluminate catalysts LaMxAl2 -xO19 - δ （ M = Fe, Ce, FeCe） were prepared by co-precipitati- on method. The effects of various ions substitution on crystal structure and the properties of the catalysts were investigated by means of XRD, H2-TPR and activity evaluation for denitrification. The results showed that Fe ions were apt to enter crystal lattice of hexaaluminate to form complete hexaaluminate phase. LaFeAl11O19-δ catalyst possessed good low-temperature denitrifieation activity. Ce ions were difficult to enter crystal lattice of hexaaluminate, and existed mainly in the form of CeO2. LaCeAl11 Ol9-δ catalyst had good catalytic activity at high temperature. After the introduction of SO2 , the denitrification activity of both aforesaid hexaaluminate catalysts declined to some extent, and LaFeA111 O19-δ catalyst was poisoned by SO2 more seriously. The activity of denitrifieation and sulfur tolerance of LaFeCeAllo O19-δ catalyst were enhanced due to the synergistic effect between Fe and Ce ions.