Solution combustion synthesis of LaxSm1−xMn2O5 nanoparticles and their electrocatalytic performances for Al-air batteries

Abstract Compared the most reported synthesis methods, a series of La x Sm 1−x Mn 2 O 5 (x = 0, 0.1, 0.3, 0.5) catalysts were first synthesized through sol-gel solution combustion synthesis with a short cycle and high yield. The main impact of different La/Sm molar ratios is the amount of surface adsorbed oxygen (O ads ) and surface Mn 4+ ions as revealed by XPS results. Electrochemical properties are characterized by rotating disk electrode (RDE) and the full dischargeable Al-air battery with 4 M NaOH electrolyte. The measurements of RDE reveal that the electron transfer number of La x Sm 1−x Mn 2 O 5 (x = 0, 0.1, 0.3, 0.5) are all closed to 4, and the sample prepared with x = 0.1 possesses the most excellent electrocatalytic activity for oxygen reduction reaction (ORR) and good discharge performance in alkaline medium. All of the above results indicate that the La x Sm 1−x Mn 2 O 5 (x = 0, 0.1, 0.3, 0.5) are promising catalysts with a high catalytic activity toward ORR.