Defective Ce–Mn solid solution loaded with Pd single atoms for an enhanced methane combustion reaction

Abstract

Methane combustion reactions hold significant promise for addressing environmental issues, particularly the greenhouse effect attributed to anthropogenic emissions. However, current catalysts face challenges in simultaneously achieving low-temperature activity and high-temperature stability. In this work, a CeMn solid solution decorated with palladium single atoms (Pd/CeMn-AR) was synthesized via a one-pot auto-redox method. Experimental findings indicate that the Pd/CeMn-AR catalyst demonstrates favorable activity and stability in the methane oxidation reaction. Specifically, the T₉₀ of Pd/CeMn-AR reaches 543 °C, significantly better than its Pd/CeO₂ (627 °C), Pd/MnO_x (634 °C) and Pd/CeMn-CP (557 °C) counterparts. Furthermore, after 10 hours of continuous reaction at elevated temperatures of 550 °C and 650 °C, the Pd/CeMn-AR catalyst retains more than 95% of its initial activity. Mechanistic investigations reveal that the autoxidative synthesis strategy enhances the exposure of oxygen vacancies, promotes the adsorption of substrates, and accelerates the oxidative conversion of intermediates, ultimately improving the catalytic efficiency.