CAJ | 학술논문

采用等体积浸渍法制备了一系列不同 MnOx 含量的 MnOx/Ce0.7Zr0.2La0.1O2-Al2O3(Ce0.7Zr0.2La0.1O2/Al2O3质量比=1)催化剂,并用 X 射线衍射、低温 N2吸附-脱附、X 射线光电子能谱、O2程序升温脱附和 H2程序升温还原等手段对催化剂进行了表征,考察了催化剂催化柴油车排放碳烟颗粒物燃烧的反应性能.结果表明,催化剂表面吸附的活性氧物种和 MnOx 的低温区还原性能是决定催化剂活性的两大关键因素.当 MnOx 负载量为5%时,催化反应所需的活性氧减少,因而活性降低;但 MnOx负载量增至10%时,催化剂中 Mn 物种的可还原量提高,从而增加其活性;增至20%时, MnOx 与表面吸附氧物种的可还原量间达平衡最佳值,活性最佳,碳烟起燃温度比无催化剂时降低了179 oC;负载量达30%后,由于载体表面吸附氧物种数量的降低和还原峰温的上升使催化剂活性下降.
채용등체적침지법제비료일계렬불동 MnOx 함량적 MnOx/Ce0.7Zr0.2La0.1O2-Al2O3(Ce0.7Zr0.2La0.1O2/Al2O3질량비=1)최화제,병용 X 사선연사、저온 N2흡부-탈부、X 사선광전자능보、O2정서승온탈부화 H2정서승온환원등수단대최화제진행료표정,고찰료최화제최화시유차배방탄연과립물연소적반응성능.결과표명,최화제표면흡부적활성양물충화 MnOx 적저온구환원성능시결정최화제활성적량대관건인소.당 MnOx 부재량위5%시,최화반응소수적활성양감소,인이활성강저;단 MnOx부재량증지10%시,최화제중 Mn 물충적가환원량제고,종이증가기활성;증지20%시, MnOx 여표면흡부양물충적가환원량간체평형최가치,활성최가,탄연기연온도비무최화제시강저료179 oC;부재량체30%후,유우재체표면흡부양물충수량적강저화환원봉온적상승사최화제활성하강.
A series of MnOx/Ce0.7Zr0.2La0.1O2-Al2O3 supported catalysts with the Ce0.7Zr0.2La0.1O2:Al2O3 mass ratio of 1:1 and different MnOx loadings were prepared by the incipient wetness method. The catalysts were characterized by X-ray diffraction, low temperature N2 adsorp-tion-desorption, X-ray photoelectron spectroscopy, O2 temperature-programmed desorption, and H2 temperature-programmed reduction. The catalytic performance of these catalysts for the combustion of diesel soot was investigated. It is found that surface-adsorbed active oxygen species and low-temperature reducibility of MnOx are the determinants of catalytic activity. When the MnOx loading is 5%, the catalyst activ-ity decreases owing to the loss of active oxygen species, which are necessary for the catalytic combustion. When the MnOx loading is in-creased to 10%, the catalyst activity is dramatically increased because of the enhanced reducible manganese species. Interestingly, the opti-mal values for reducible manganese species and surface-adsorbed oxygen species can be achieved in the catalyst with 20% MnOx, and so the catalyst exhibits the best catalytic activity, giving a light-off temperature about 179 oC lower than that of the non-catalytic soot combustion. With a further addition of MnOx species up to 30%, its catalytic activity is deteriorated mainly due to the decrease in surface-trapped oxygen species and upper shift of the reduction temperature.