Non-thermal plasma coupled with MOF-74 derived Mn-Co-Ni-O porous composite oxide for toluene efficient degradation.

A novel strategy for removal of toluene by non-thermal plasma (NTP) coupled with metal-organic frameworks (MOFs) derived catalyst was proposed in this work. The MOF-derived porous trimetallic oxide catalyst (MnCoNiOx, MCNO) was prepared by simple pyrolysis of a MOF-74(Mn-Co-Ni) precursor. We found that the MCNO material can well synergy with NTP in total decomposition of toluene owing to its high specific surface area, regular porous structure and excellent reducibility, which endow superior catalytic activity and CO2 selectivity of NTP-MCNO system compared to that of NTP-MnOx, NTP-CoOx and NTP-NiOx. For instance, the toluene degradation efficiency can reach up to 75.7% in NTP-MCNO system with a low specific input energy of 101 J/L, much higher than that of NTP-MnOx (59.3%), NTP-CoOx (70.9%), NTP-NiOx (65.0%) and NTP alone (42.9%). Moreover, the formed ozone (O3) can be well-controlled by the NTP-MCNO system due to the spinel-type oxides (MCNO) derived from MOF could generate more open-formwork structure and improve the mobility of oxygen. The results of this work would shed light on rational design and preparation of spinel-type oxides for oxidation applications, which provides guidance for further improvement of plasma-catalysis system.