Carbon-Supported Pt doped Double Perovskites for Multifunctional Electrocatalysis in Alkaline Media

Abstract

Pt-substituted La2Fe2-yPtyO5+δ double perovskites (y = 0.01, 0.05, and 0.10) were synthesized by the Pechini method and investigated as electrocatalysts for alkaline energy-conversion applications. XRD, SEM, TEM, and XPS were employed to characterize the phase composition, microstructure, and surface chemical states as a function of Pt substitution. XRD confirmed the formation of phase-pure double-perovskite structures and revealed lattice modulation associated with Pt incorporation at the B-site. Microstructural analysis showed porous and agglomerated particles, with composition-dependent variations in morphology and crystallite characteristics, indicating that Pt substitution influenced defect chemistry and microstrain. XPS revealed modifications in the surface electronic environment, including changes in the Fe redox distribution and the formation of oxygen-deficient surface species. Pt was incorporated at low concentrations without disrupting the overall perovskite structure and exhibited multiple oxidation states depending on its content. The double perovskites were supported on Vulcan XC-72 carbon to form La2Fe2-yPtyO5+δ/C composites. Their electrocatalytic activity toward the hydrogen and oxygen evolution reactions (HER and OER, respectively) was evaluated in alkaline media and benchmarked against commercial Pt/C. The results demonstrated the potential of Pt-substituted double perovskite/carbon composites as bifunctional electrocatalysts for alkaline energy-conversion applications, including anion exchange membrane electrolyzers (AEMEs) and zinc-air batteries (ZABs).

Keywords: Pt-substituted double perovskites; Alkaline electrocatalysis; Water splitting.