氧化还原沉淀法制备Mn-Ce-Co-Ox/PPS滤料及其低温SCR活性

先用十二烷基硫酸钠（SDS）对聚苯硫醚（PPS）滤料进行表面改性，随后通过氧化还原沉淀法制得不同质量比的Mn-Ce-Co-O_x/PPS复合滤料。考察了复合滤料在低温选择性催化还原（SCR）反应过程中的催化活性，并通过XRD、FESEM、TEM和XPS等表征手段对复合滤料的结构及性能进行表征分析。结果表明，Mn-Ce-Co-O_x/PPS复合滤料在120-160 ℃时的脱硝效率达到86%-100%，明显优于超声法制备的Mn-Ce-Co-O_x/PPS-UM复合滤料的低温SCR活性，且1.2Mn-Ce-Co-O_x/PPS复合滤料的活性最优。1.2Mn-Ce-Co-O_x/PPS复合滤料中MnO₂、Ce₂O₃、CeO₂、CoO、Co₃O₄以蜂窝状形式均匀分散在PPS纤维表面，且呈弱结晶性结构；其较高的Ce³⁺/（Ce³⁺+Ce⁴⁺）比值和Co元素浓度是该1.2Mn-Ce-Co-O_x/PPS复合滤料具有优异低温SCR活性的主要原因。此外，与Mn-Ce-Co-O_x/PPS-UM复合滤料相比，1.2Mn-Ce-Co-O_x/PPS复合滤料也具有良好的抗H₂O和抗SO₂性能。

Preparation of the Mn-Ce-Co-Ox/PPS filter material by a redox method and its activity in the low-temperature selective catalytic reduction of NOx

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 Ce³⁺/(Ce³⁺+Ce⁴⁺) ratio and high concentration of Co; moreover, honeycomb-like MnO₂, Ce₂O₃, CeO₂, CoO and Co₃O₄ 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 H₂O and SO₂.