Fabrication of samarium oxide embedded carbon nanotubes electrocatalyst for oxygen evolution reaction

Abstract The economically unfeasible electrochemical breakdown of water is linked to the production of materials with low overpotential using a simple method. The study demonstrates the fabrication and use of samarium oxide (Sm 2 O 3 ) on carbon nanotubes (CNTs) as an effective and long‐lasting electrocatalyst for oxygen evolution reaction (OER). X‐ray diffraction analysis confirms fabrication of Sm 2 O 3 embedded CNTs (Sm 2 O 3 /CNTs) phases with 0.052 nm lattice strain, while scanning electron microscopy structural analysis shows a ball‐like shape with 78 nm average particle size. The synthesized catalyst performs well, attaining a current density of 10 mA cm −2 and having an onset potential of 1.33 V versus reversible hydrogen electrode (RHE). In contrast to Sm 2 O 3 and CNT, which exhibit higher overpotentials of 311 and 342 mV with corresponding Tafel slopes of 62 and 83 mV dec −1 , respectively, Sm 2 O 3 ‒CNT has a low Tafel slope of 38 mV dec −1 and a lower overpotential of 276 mV. With a current density of more than 50 mA cm −2 , the catalyst demonstrated remarkable stability over 180 h. The electrochemical impedance spectroscopy analysis attributed the robust ionic conductivity of K⁺ ions, their small hydration sphere, and reduced electrode impedance to their R ct value of 3.4 Ω. The composite potential of CNTs and Sm 2 O 3 as a long‐term and effective OER electrocatalysis substitute has been demonstrated through promising results.