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 NdFeO_3−δ, transforming it into a double perovskite structure. The resulting Nd_0.8Ba_1.2Fe_1.6Ni_0.4O_6−δ catalyst achieved an overpotential of 320 mV at 10 mA cm⁻² 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, which enhances electronic conductivity. Meanwhile, B-site Ni incorporation strengthens metal–oxygen covalency and decreases 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⁻¹, compared to 114.85 mV dec⁻¹ for single-site modified Nd_0.8Ba_1.2Fe₂O_6−δ and 154.34 mV dec⁻¹ for unmodified NdFeO_3−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.