Mn基金属有机骨架(MOFs)催化剂制备及介质阻挡放电(DBD)等离子体协同催化降解甲苯

Preparation of Mn-based metal-organic frameworks(MOFs)catalysts and its synergistic catalysis on toluene degradation with dielectric barrier discharge(DBD)plasma

采用溶剂热合成法制备了Mn-MOF-74和Mn-TPA-DMF两种Mn基MOFs催化剂,并用XRD、FTIR、SEM、BET和XPS等对催化剂进行了表征.采用催化剂与介质阻挡放电(DBD)等离子体反应器协同系统评估甲苯气体降解性能.研究结果表明,采用DBD/Mn-MOF-74催化降解甲苯,当能量密度为830.57 J·L^(-1)、氧气体积分数为4%时,甲苯降解率达97.3%,CO_(2)选择性为49.4%,矿化度为72.8%,能量效率为5.77 g·kWh^(-1).与单独DBD相比,Mn基MOF催化剂的引入提高了甲苯的去除率、CO_(2)的选择性和碳平衡,有效抑制了副产物O_(3)和NO_(x)的生成(下降了约50%).与Mn-TPA-DMF相比,Mn-MOF-74表现出更优越的等离子体协同催化性能.结合催化剂的表征结果及性能评估,推测Mn基MOFs大的比表面积、表面吸附氧(Oads)、Mn多价态(Mn^(2+),Mn^(3+),Mn^(4+))之间的电荷循环转移是影响催化性能的关键因素.

In this study,two Mn-based metal-organic frameworks(MOFs)catalysts,termed as Mn-MOF-74 and Mn-TPA-DMF,were prepared by solvothermal method,and were characterized by XRD,FTIR,SEM,BET and XPS.In addition,a synergistic system of catalyst and dielectric barrier discharge(DBD)plasma reactor was applied to evaluate the gas degradation performance of toluene.Our results show that the removal efficiency of toluene is 97.3%,the selectivity of CO_(2) is 49.4%,the degree of mineralization is 72.8%,and the efficiency of energy is 5.77 g·kWh^(-1),respectively,when the energy density is 830.57 J·L^(-1) and,the O_(2) volume fraction is 4%in the DBD+Mn-MOF-74 catalytic system.In comparison with DBD,the adding of Mn-based MOFs catalysts enhanced toluene removal efficiency effectively,as well as CO_(2) selectivity and carbon balance.Moreover,suppressed the byproducts,e.g.,the yield of O_(3) and NO_(x) decreased by about 50%.Besides,Mn-MOF-74 shows better plasma synergistic catalytic performance compared to Mn-TPA-DMF.On the basis of catalyst characterization and performance evaluation,we could infer that the key factors impacting catalytic performance for DBD catalysis are attributed to larger surface areas,more surface absorbed oxygen(Oads),and charge cycle shift between polyvalent Mn(Mn^(2+),Mn^(3+),Mn^(4+)).