Sm1-XSrxMnO3 (X=0.1, 0.2, 0.3, and 0.4) perovskite (SSM) with a-site doping optimized as oxygen reduction reaction (ORR) electrocatalyst

A highly selective, stable and efficient non-precious metal catalyst is crucial for alkaline fuel cell applications. Recently, rare earth-based perovskite showed improved oxygen reduction reaction (ORR) which is analogous to commercial Pt/C. In this paper, strontium doped SmMnO3 (Sm1-xSrxMnO3 (x = 0.1, 0.2, 0.3, and 0.4)) were synthesized by sol-gel route. The structure, valence state, and morphology of these samples were analyzed and oxygen adsorption behavior was investigated. Further, using the RRDE electrode (rotating ring disk electrode) the electro-catalytic behavior of the prepared catalyst toward ORR were investigated. The absorption of molecular oxygen by SmMnO3 catalyst was improved and the Mn valence state was tailored by doping Sr into the crystal lattice of SmMnO3. Sm1-xSrxMnO3 (x = 0.3) displayed highest ORR activity and stability among the synthesized electrocatalyst, with kinetic current density and onset potentials of 1.15 mA/cm2, and 0.92 V vs RHE, respectively. High stability and electron transfer number around 4 makes the prepared electrocatalyst a viable alternate to commercial Pt/C for alkaline fuel cell application.