Synergistic effect of a bamboo-like Bi2S3 covered Sm2O3 nanocomposite (Bi2S3–Sm2O3) for enhanced alkaline OER

Abstract

The availability of hydrogen energy from water splitting through the electrocatalytic route is strongly dependent on the efficiency, durability, and cost of the electrocatalysts. Herein, a novel Bi₂S₃-covered Sm₂O₃ (Bi₂S₃–Sm₂O₃) nanocomposite electrocatalyst was developed by a hydrothermal route for the oxygen evolution reaction (OER). The electrochemical properties were studied in 1.00 mol KOH solution after coating the target material on the stainless-steel substrate (SS). Physical analysis via XRD, FTIR, IV, TEM/EDX, and XPS revealed that the Bi₂S₃–Sm₂O₃ composite possesses metallic surface states, thereby displaying unconventional electron dynamics and purity of phases. The Bi₂S₃–Sm₂O₃ composite shows outstanding OER activity with a low overpotential of 197 mV and a Tafel slope of 74 mV dec⁻¹ at a 10 mA cm⁻² current density as compared to pure Bi₂S₃ and Sm₂O₃. Meanwhile, the composite catalyst retains high stability even after 100 h of the chronoamperometry test. Thus, this work unveils a new avenue for the speedy flow of electrons, which is attributed to the synergetic effect between Bi₂S₃ and Sm₂O₃, as well as enriched interfacial defects, which exhibit greater oxygen adsorption capability with improved electronic assemblies in the active interfacial region. In addition, the introduced porous structure in core–shell Bi₂S₃–Sm₂O₃ provides extraordinary electrical properties. Thus, this article offers a realistic framework for electrochemical energy generation.