Boosting catalytic activity of Pd/La_xCe_1-xMnO₃ catalysts in methane combustion by a plasma-treated strategy

An innovative plasma-treated strategy was employed to prepare La_xCe_1-xMnO₃ (LCMO) perovskite oxides. Pd nanoparticles were loaded onto plasma-treated (P) and air-calcined (T) LCMO respectively, forming the corresponding Pd/LCMO catalysts. The results indicated that the introduction of Pd and plasma treatment largely boost the catalytic activity in methane combustion. Among these catalysts, the Pd/LCMO-P catalyst shows the best performance in CH₄ oxidation, giving T₉₀ of 425 °C. It was revealed that the morphology structure and surface defects were strongly affected by plasma treatment, further affecting the dispersion and chemical state of Pd species via surface interaction. The superior performance should be ascribed to the good redox properties (high Mn⁴⁺/Mn³⁺ ratio), rich surface-active oxygen species, and enhanced oxygen mobility (weakened Pd-O and Mn-O chemical bonds). Besides, the distributions of cerium in the surface and crystal lattice of LMO also improved metal-support interaction and the oxygen mobility, that boosted CH₄ oxidation. This plasma-treated strategy provided an effective path to develop the efficient combustion catalyst for superior performance.