Abstract:
A series of Mn-Ce-Co-O
x/PPS composite filter materials with different mass ratios were obtained by modifying the pristine polyphenylene sulfide (PPS) filter material with sodium dodecyl sulfate (SDS) and then treated by a redox precipitation method. The Mn-Ce-Co-O
x/PPS composite filter materials were characterized by XRD, FESEM, TEM and XPS; their catalytic performance in the low-temperature selective catalytic reduction (SCR) of NO
x was then investigated. The results show that the Mn-Ce-Co-O
x/PPS composite filter materials obtained by the redox method presents higher low-temperature SCR activity than the Mn-Ce-Co-O
x/PPS-UM composite filter material fabricated via the ultrasonic method; over the former material, the NO
x conversion reaches 86%-100% at 120-160℃. Among them, the 1.2Mn-Ce-Co-O
x/PPS composite filter material displays the highest SCR activity, which is probably ascribed to the high Ce
3+/(Ce
3++Ce
4+) ratio and high concentration of Co; moreover, honeycomb-like MnO
2, Ce
2O
3, CeO
2, CoO and Co
3O
4 are uniformly distributed on the PPS filter material in the weak crystalline structure. In comparison with Mn-Ce-Co-O
x/PPS-UM, the 1.2Mn-Ce-Co-O
x/PPS composite filter material also exhibits higher resistance to H
2O and SO
2.