Enhanced oxygen vacancy over Mg-doped LaCo1-xMgxO3 perovskite catalysts for toluene catalytic combustion: insight into the role of magnesium.

Oxygen vacancy construction of perovskite catalysts is a hot topic in the study of VOCs catalytic oxidation. How to stably increase the concentration of oxygen vacancy without damaging the perovskite structure needed to be further studied. Herein, the different Mg-doped LaCo1−xMgxO3 (x = 0, 0.05, 0.10, 0.15, 0.20) perovskite were performed to research the toluene catalytic combustion. Results show that the designed LaCo0.85Mg0.15O3 catalyst with highest catalytic performance of toluene (T90 = 231 °C) and lower Ea (72.9 kJ/mol). Oxygen vacancy generated over LaCo1−xMgxO3 perovskite catalyst due to the lattice distortion of CoO6 via the doped of low valence magnesium. Moreover, the strong interaction between cobalt and magnesium promoted the reducibility and oxygen mobility and thus enhanced the toluene removal efficiency. In addition, Co-O-Mg structure was conducive to the formation of more active Co3+ and surface active oxygen species. Moreover, the toluene catalytic combustion mechanism was investigated by in situ DRIFTS, the benzoic acid, maleate were the main intermediate products. In this paper, a facilitate method of B-site doped over perovskite catalyst with low valence state and larger ionic radius was proposed, which gave a feasible way to improving the concentrate of oxygen vacancy.