A-Site Regulated (PrBa)xCo1.5Fe0.5O6−δ Double Perovskite Oxides: Highly Active and Durable Electrocatalysts for the Enhanced Oxygen Evolution Reaction

Abstract

Oxygen evolution reaction (OER) represents a significant bottleneck in many energy technologies such as electrochemical water splitting, metal-oxygen (O) batteries, and solid oxide fuel cells (SOFCs) because of the complexity of the reaction process. Double perovskite oxides (ABO₃), recognized for their compositional flexibility, have emerged as excellent OER activity and stability. This study investigates the catalytic potential of A-site-ordered double ABO₃ with (PrBa)_xCo_1.5Fe_0.5O_6δ (PBCF_−x, x = 0.9–1.1) in alkaline media. The results reveal that PBCF_−0.9, characterized by an A-site-deficient composition, exhibits exceptional OER activity. It demonstrates a low Tafel slope of 76.12 mV⋅dec⁻¹ and a low overpotential (η) of 270 mV at 10 mA⋅cm⁻². Notably, the intrinsic OER activity of PBCF_−0.9 is 25% higher than that of the stoichiometric PBCF_−1.0. Additionally, PBCF_−0.9 exhibits remarkable durability, as evidenced by its stable performance during a 6-h chronopotentiometry (CP) test and minimal microstructural changes. These results underscore the effectiveness of A-site deficiency in optimizing the structure of double ABO₃ for improved OER performance. This approach presents a promising strategy for designing highly efficient, stable, and inexpensive catalysts for energy-related applications.