Surface optimization of double perovskite oxide La2NiFeO6 for toluene catalytic oxidation through control of cation non-stoichiometry

Abstract

In recent years, perovskite oxides have gained significant attention for their potential in various heterogeneous catalysis fields, particularly in the catalytic oxidation of volatile organic compounds (VOCs). Despite this, further exploiting the potential of perovskite-based catalysts remains a major challenge. This study proposes a facile method to regulate the physical-chemical properties of double perovskite oxide La2NiFeO6 catalysts by precisely controlling the bulk A-site deficiency. The strategy enables the modulation of surface chemical environment, including the valence of surface-active sites and the distribution of oxygen species. The results reveal a volcano-like relationship between the A-site/B-site cation ratio and toluene catalytic oxidation reactivity. Sample L1.85NFO possesses superior performance for toluene catalytic oxidation with T90 at about 253 ℃, and the normalized reaction rate is twice of stoichiometric sample LNFO. Various characterizations, such as XPS, BET, SEM, and EPR were employed to study the surface properties. Surface active sites with higher oxidizability and more active oxygen species were also achieved. This work not only improves the catalytic performance of perovskite oxide at low temperatures but also contributes significantly to the practical application of low-cost perovskite oxide material in industrial settings.