Excellent degradation of toluene by non-thermal plasma coupled with M-BTC MOF（M=Mn, Cu, Ce）

In view of the unsatisfactory synergy between plasma technology and catalyst, a series of M-BTC MOFs (M=Mn, Cu, Ce) were introduced to couple with non-thermal plasma using for toluene degradation. M-BTC MOFs containing multi-carboxylic groups were successfully synthesized and presented the excellent crystallinity, morphology and thermal stability. DBD-catalysis systems presented the more excellent toluene degradation performance than single DBD alone system. Due to the porous structure and the multivalent form of manganese, the highest toluene degradation efficiency of 96.27%, the energy efficiency of 22.32 g/kW·h, the CO2 selectivity of 53.5% and the mineralization degree of 70.17% were acquired for DBD coupled with Mn-BTC under SED of 766.35 J/L. Besides, DBD/Mn-BTC had the lowest ozone and NOx production. Moreover, the toluene degradation mechanism was analyzed by plasma emission spectra analysis, XPS spectra and GC-MS diagram analysis. It indicated plasma discharge can produce abundant free radicals and reactive species to decompose toluene firstly, and the residual toluene and intermediates in the gas can be then adsorbed on Mn-BTC and further oxidized by metal active species. Furthermore, more reactive oxygen species will be generated by activating ozone through Mn-BTC, which was beneficial for toluene degradation.