【摘要】 采用浸渍法分别制备了Mn-Co-La-Ce/Al₂O₃、Mn-Co-Ce/Al₂O₃和Mn-La-Ce/Al₂O₃多元金属催化剂,利用BET、XPS、O₂-TPD和FT-IR对反应前后的Mn-Co-La-Ce/Al₂O₃进行表征分析,研究了其在放电低温等离子体（NTP）协同催化体系中对对二甲苯的催化降解效果,以及催化降解条件（对二甲苯初始浓度、氧含量、气量等）对其降解效率影响,应用气相色谱-质谱分析了NTP协同催化剂降解对二甲苯反应后的有机副产物,探讨了NTP协同催化体系降解对二甲苯的机理.结果表明,等离子体将增加催化剂的表面晶格氧释放的强度.La掺杂能提高多元催化剂O_ads和O_lat的结合能,O_ads占比达54.67%,提高O_ads含量达1.24%.与单独NTP降解相比,NTP协同多元催化剂的降解效率提高达50%以上,CO₂选择性也提高约30%.NTP协同Mn-Co-La-Ce催化反应中,初始浓度、气量与氧含量对降解效率的影响呈负相关,电压对降解效率的影响呈正相关,同时可以有效地抑制O₃、NO_x等副产物的产生量.推测协同降解机理主要有3条途径.研究结果可为等离子体协同催化降解对二甲苯废气提供一定的理论支撑.更多还原

【Abstract】 The Mn-Co-La-Ce/Al₂O₃,Mn-Co-Ce/Al₂O₃ and Mn-La-Ce/Al₂O₃ multiple metal catalysts were prepared by impregnation,respectively.The characterization of the Mn-Co-La-Ce/Al₂O₃ in before and after the reaction were performed using BET,XPS,O₂-TPD,and FT-IR.The catalytic degradation efficiency of p-xylene in the discharge non-thermal plasma （NTP） synergistic catalytic system were studied.The effects of catalytic reaction conditions （initial concentration,oxygen content,and gas-flow rate）on degradation efficiency were investigated.The organic by-products of degradation for NTP cooperative catalyst were analyzed by using GC-MS,and the degradation mechanism of NTP synergistic catalytic system was discussed.The results show that the plasma will increase the strength of the lattice oxygen release on the surface of the catalyst.La doping in multiple catalysts can improve the binding energy of O_ads and O_lat of the catalyst,with O_ads accounting for 54.67%,and improve the O_ads content of the catalyst by up to1.24%.Compared with the NTP alone,the degradation efficiency of the NTP synergistic multiple catalyst was increased by more than 50%,and the CO₂ selectivity was also increased by about 30%.In the NTP synergistic Mn-Co-La-Ce catalytic reaction,the effect of initial concentration,gas volume and oxygen content on degradation efficiency was negatively correlated,and the effect of voltage on degradation efficiency was positively correlated,which can effectively inhibit the production amount of by-products such as O₃ and NO_x.It is speculated that there are three main pathways for the degradation mechanism of NTP synergistic catalysts.The results can provide some theoretical support for the NTP synergistic catalyst for degradation of p-xylene.更多还原