载体对Pd-Cu/活性炭催化剂在消除卷烟主流烟气中CO活性的影响

Effect of Supports on the Catalytic Performance of Pd-Cu/Activated Carbon Catalyst for Eliminating CO in Cigarette Smoke

采用等体积浸渍法制备了Pd-Cu/活性炭催化剂,用脉冲反应考察了催化剂对模拟卷烟主流烟气(4.4CO-4.2H2O-19.2O2-72.2He)(体积分数,%)中CO的常温催化氧化性能,系统研究了不同的活性炭载体对催化剂的CO常温氧化活性的影响.研究表明,在室温条件下,催化剂对CO氧化反应的活性顺序为:椰壳活性炭为载体的催化剂(CAC)<木质活性炭为载体的催化剂(WAC)<超级活性炭为载体的催化剂(SAC),并且活性炭载体对催化剂的反应诱导期也存在显著的影响.对催化剂的表征结果表明,不同活性炭载体表面上含氧官能团含量不同,影响催化剂表面Pd和Cu的存在状态,使得SAC催化剂上的Pd只以Pd2+形式存在,而CAC和WAC催化剂上的Pd以Pd2+和Pd0形式存在,导致SAC催化剂比CAC和WAC两种催化剂具有更好的CO催化氧化活性.使用催化剂接装的三段式复合滤嘴试验卷烟,与对照卷烟相比,卷烟主流烟气中CO的释放量都有所降低,其中添加SAC催化剂的效果最为明显.如果将Pd的负载量增加为3.4%(w),SAC催化剂对卷烟主流烟气中CO的去除率高达25.4%.

Pd-Cu/activated carbon catalysts were prepared by wetness impregnation and their performance in the room-temperature catalytic oxidation of the pulse reaction of carbon monoxide were investigated using simulated cigarette smoke gas consisting of 4.4 CO-4.2 H2O-19.2 O2-72.2 He（volume fraction,%）.The effect of different activated carbon supports on catalytic performance was investigated in detail.The results show that at room temperature the order of catalytic performance for CO oxidation is：the catalyst supported on coconut activated carbon（CAC）wood activated carbon（WAC）super activated carbon（SAC）.The characterization results indicate that oxygen-containing functional groups on the surface of the activated carbon affect the states of Pd and Cu on the surface of the catalysts.Pd2＋ and Pd0 are also present on the surfaces of the CAC and WAC catalysts but only Pd2＋ is present on the surface of the SAC catalysts,which results in better catalytic activity for SAC than that of the CAC and WAC catalysts.When the ternary composite filter was prepared by inserting the catalyst between the cigarette filter and the acetate filter rod,the smoking tests showed that the amount of CO in the main cigarette smoke decreased noticeably.The SAC catalyst reduced CO by 25.4% when the amount of Pd in the catalyst increased to 3.4%（w）.