Degradation of toluene by DBD plasma catalytic technology with CoMn-BTC/ Ti3C2Tx composites

Dielectric barrier discharge (DBD) plasma catalytic technology is considered as one of the most effective methods for elimination of diluted volatile organic compounds (VOCs) due to its advantages of high efficiency, low cost, and wide applicability. The design of highly efficient catalytic materials is a notable challenge for this technology. In this study, Ti 3 C 2 T x , GO, and NiMn 2 O 4 , which possess a large specific surface area and high electron transport properties, were introduced as catalyst supports. These materials were combined with CoMn-BTC to synthesize three types of supported composite catalysts, which were used for the DBD-assisted VOCs degradation. Characterization analyses, including XRD , FTIR and SEM, indicated that CoMn-BTC was successfully integrated with the three supports. The large specific surface area and more oxygen vacancy for CoMn-BTC/Ti 3 C 2 T x than bulk CoMn-BTC explained the enhanced toluene removal efficiency and mineralization, CO 2 selectivity , along with suppression of undesirable O 3 and NO x . Characterization of CoMn-BTC/Ti 3 C 2 T x catalysts before and after the plasma catalytic process indicated that high adsorbed oxygen species and the redox cycles between Co 3 + /Co 2+ and Mn 2+ /(Mn 4+ , Mn 3+ ) species can effectively promote toluene and intermediates oxidation . Furthermore, GC-MS analysis of the organic by-products in the effluent gas revealed that the amounts of intermediates such as nitrophenol reduced in the CoMn-BTC/Ti 3 C 2 T x compared with CoMn-BTC, further demonstrating that CoMn-BTC/Ti 3 C 2 T x had excellent catalytic activity. At last, the possible reaction pathways of toluene degradation in plasma-catalytic system was proposed in combination with analysis results of GC-MS, optical emission spectroscopy and properties of the catalyst before and after discharge reaction. • CoMn-BTC/Ti 3 C 2 T x composite was used for plasma-assisted toluene degradation. • CoMn-BTC/Ti 3 C 2 T x catalyst exhibited higher surface area and more oxygen vacancy . • CoMn-BTC/Ti 3 C 2 T x showed higher toluene conversion efficiency and lower O 3 and NO x . • Oxygen vacancy and redox properties can promote ROS production and toluene oxidation. • Possible reaction mechanism of toluene catalytic oxidation was proposed.