Lanthanide based double perovskites: Bifunctional catalysts for oxygen evolution/reduction reactions

In this work, we are reporting the facile synthesis of double perovskite oxide materials LnBa(0.5)Sr(0.5)Co(1.5)Fe(0.5)O(6) (LnBSCF, Ln = Pr, Nd, Sm, and Gd) using citrate-nitrate based solgel method. These double perovskite oxide materials exhibit bifunctional catalytic activity for the oxygen evolution reaction (OER) and oxygen reduction reaction (ORR). The phase formation and structure of the prepared oxides have been determined by powder X-ray diffraction, SEM analysis. Presence of various phases is analyzed and quantified by mean of Le-Bail refinement of XRD profiles. SEM analyses confirm the morphology and composition of prepared catalysts. Electrochemical measurements, e.g. Linear Sweep Voltammetry, Cyclic Voltammetry and Electrochemical Impedance spectroscopy were used to study catalytic performance of prepared catalyst towards both oxygen evolution and oxidation reduction reactions in alkaline solution. Better catalytic performance was obtained in case of double perovskites as compared to parent perovskite for both reactions. Best catalytic performance was observed for Gd based double perovskite. (C) 2021 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Automated summary

In this study, double perovskite oxide materials were synthesized using a citrate-nitrate sol-gel method, exhibiting bifunctional catalytic activity for OER and ORR. Phase formation and structure were analyzed by XRD and SEM, confirming morphology and composition. Electrochemical tests showed superior catalytic performance of double perovskites compared to parent perovskite, with Gd-based catalysts showing the best performance.