Nonthermal plasma catalysis for toluene decomposition over BaTiO3-based catalysts by Ce doping at A-sites: The role of surface-reactive oxygen species

The insights on the primary surface-reactive oxygen species and their relation with lattice defects is essential for designing catalysts for plasma-catalytic reactions. Herein, a series of Ba1-xCexTiO3 perovskite catalysts with high specific surface areas (68.6-85.6 m(2)g(-1)) were prepared by a facile in-situ Ce-doping strategy and investigated to catalytically decompose toluene. Combining the catalysts with a nonthermal plasma produced a significant synergy effect. The highest decomposition efficiency (100%), COx selectivity (98.1%), CO2 selectivity (63.9%), and the lowest O-3 production (0 ppm) were obtained when BC4T (Ce/Ti molar ratio = 4:100) was packed in a coaxial dielectric barrier discharge reactor at a specific input energy of 508.8 J L-1. The H-2-TPR, temperature-programmed Raman spectra, EPR and OSC results suggested that superoxides (center dot O-2(-)) were the primary reactive oxygen species and were reversibly generated on the perovskite surface. Molecular O-2 was adsorbed and activated at the active sites (Ti3+-V-o) via an electron transfer process to form center dot O-2(-) Surface-adsorbed center dot O-2(-) had a greater effect on the heterogeneous surface plasma reactions than the dielectric constant, and enhanced the toluene decomposition and intermediate oxidation. A possible reaction path of toluene decomposition was also proposed.

Automated summary

The Ba1-xCexTiO3 perovskite catalysts prepared by Ce-doping strategy showed efficient catalytic decomposition of toluene and significant synergy when combined with nonthermal plasma. Superoxides were identified as the primary reactive oxygen species generated reversibly on the catalyst surface via an electron transfer process, enhancing the heterogeneous surface plasma reactions.