Surface tuning of 3DOM LaFe_0.6Mg_0.4O₃ perovskite by acid etching to enhance catalytic performance for soot combustion

Acid etching is one of the most widely used methods for surface tuning of perovskite. In this paper, 3DOM LaFe_0.6Mg_0.4O₃ was synthesized by a colloidal crystal template method, and was further etched by acetic acid at different times, which made the Mg element at the B-site of perovskite selectively dissolved. Through analysis of multiple characterization results, the introduction of B-site deficiency by acid etching could not only enhance oxygen vacancies, form the Fe⁴⁺/Fe³⁺ redox cycles on the surface of the catalyst, but also generate mesopores structure and increase the specific surface area. After acid treatment, the soot and NO oxidation performances were improved. Among all the as-prepared catalysts, 3DOM LaFe_0.6Mg_0.4O₃ treated by acetic acid for 1 h (LFM-1) exhibited superior reducibility and better activity for soot combustion. The T₅₀ of LFM-1 was 417 °C under 5 % O₂/N₂ and 500 ppm NO, and the activation energy and TOF were 66 kJ·mol⁻¹ and 2.17 × 10^-3 s⁻¹, respectively. Herein, the strategy of introducing B-site deficient by acid treatment is an effective method to improve soot combustion activity, which might be applicable to other catalytic fields.