Fe-O terminated LaFeO3 perovskite oxide surface for low temperature toluene oxidation

The surface termination of catalyst is vital to heterogeneous catalytic reaction process. Inactive A-site cations exposed over the perovskite oxide materials would limit the surface activity of studied samples. In this work, the surface composed of more Fe-O termination was synthesized over the LaFeO3 perovskite oxide and it shows performance superiority than more La-O exposed samples. Combined with the characterization results, exposure of more Fe-O termination would help boost the oxygen mobility and enhance the reducibility of LaFeO3 perovskite with higher hydrogen consumption (0.088 mmol/g) than that of untreated LaFeO3 sample (0.033 mmol/g). Based on the DFT calculation and XPS analyzation, exposure of the Fe-O termination surface would decrease the formation energy of oxygen vacancy and hence boost the oxygen cycle process, which would accelerate the redox process in return. Furthermore, more Fe-O exposed surfaces would cause the effective performance enhancement for the catalytic oxidation of toluene. After 5 h surface treatment, T-50 and T-90 of LFO-5 are 255.9 degrees C and 277.3 degrees C, much lower than that of untreated sample, which are 309.7 degrees C and 332.8 degrees C, correspondingly. In the meantime, the surface treated sample possess relative good stability under 20 h test. This work would benefit for the practical application and provide a better understanding to the potential of perovskite oxides. (C) 2020 Elsevier Ltd. All rights reserved.