A rare–earth modified NiO for enhanced hydrogen and oxygen evolution in alkaline water splitting

Harnessing green hydrogen through water electrolysis stands at forefront of global energy transition, offering a clean, scalable solution to escalating climate and energy crisis. However, poor kinetics of oxygen evolution reaction (OER) remains a fundamental impediment, limiting overall efficiency of this technology. Using facile hydrothermal synthesis, we present a structurally integrated and electronically modulated bifunctional electrocatalyst, nickel oxide and dysprosium oxide nanospheres uniformly anchored on nickel foam, (NiO/Dy 2 O 3 @NF). Rare earth 4f orbital contribution of Dy 3+ , contributing substantial electronic polarization at Ni– O -Dy interface and promotes higher oxidation states of Ni (Ni 2+ /Ni 3+ ), which are essential for rate determining O–O bond formation in OER. NiO/Dy 2 O 3 @NF nanocomposite exhibit uniform nanospheres morphology having particle size (44.3 nm) with moderate agglomeration, promoting efficient electron transport and an enlarged electroactive surface area, as confirmed by SEM. In 1 M KOH, Cyclic Voltammetry analysis of NiO/Dy 2 O 3 @NF delivers low Tafel slopes of 43.2 mV dec −1 (OER), 31.8 mV dec −1 (HER), with low onset potentials of 1.43 V and −0.44 V, sequentially. EIS reveals small semicircle, resulting Rct 1.2 Ω, indicating efficient interfacial charge transport during water splitting. Notably, electrode retains 90 % of its initial current density after 50 h having negligible degradation, confirming excellent operational stability. This performance positions NiO/Dy 2 O 3 @NF as a promising candidate for integration into scalable electrolyzer systems, advancing both hydrogen energy technologies and environmental sustainability. • NiO/Dy 2 O 3 Nanocomposite fabricated via facile hydrothermal method. • Bifunctional Characteristics for OER & HER owing to enhanced active sites and porous structure. • Rare earth 4f orbital contribution of Dy 3+ results in electronic polarization. • Nanocomposite resulted lower Tafel slopes of 43.2 mV dec −1 for OER, 31.8 mV dec −1 for HER. • NiO/Dy 2 O 3 exhibited remarkable stability for 50 h, retaining 90 % of current initial current density.