Achieving High-Performance OER Catalysis with Dual-Site Modulated Fe-Based Perovskites

Abstract

Developing cost-effective, efficient oxygen evolution reaction (OER) catalysts is critical for sustainable hydrogen production through water electrolysis. While noble metal-based catalysts like RuO2 and IrO2 show high activity, their widespread adoption is limited by cost. Fe-based perovskite oxides present a more abundant alternative but typically exhibit inferior OER activities. In this study, we achieved systematic dual-site modulation by incorporating Ba at the A-site and Ni at the B-site of NdFeO3-δ, transforming it into a double perovskite structure. The resulting Nd0.8Ba1.2Fe1.6Ni0.4O6-δ catalyst achieved an overpotential of 320 mV at 10 mA/cm2 in 0.1 M KOH, significantly lower than typical Fe-based perovskites and noble metals. Ab initio simulations revealed that A-site modulation reduces the band gap, enhancing electronic conductivity, while B-site Ni incorporation strengthened metal-oxygen covalency and decreased charge-transfer energy. The synergistic effects between enhanced electronic conductivity and metal-oxygen covalency led to a significantly reduced Tafel slope of 63.23 mV/dec, compared to 114.85 mV/dec for single-site modified Nd0.8Ba1.2Fe2O6-δ and 154.34 mV/dec for unmodified NdFeO3-δ. This work provides a framework for understanding and improving performance in Fe-based perovskite OER catalysts through dual-site modulation, paving the way for more cost-effective and sustainable water electrolysis technologies.