ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Facile fabrication of cobalt sulfide-supported manganese oxide hybrid as an efficient electrode material for OER

Iqra Bibi, B. M. Alotaibi, Eman Alzahrani, Haifa A. Alyousef, Albandari . W. Alrowaily, Hidayath Mirza, and Abhinav Kumar

Department of Chemistry, Government Graduate College Taunsa Sharif, Taunsa, Pakistan

E-mail: iqrahanif852@gmail.com

Received: 19 July 2025  Accepted: 19 August 2025

Abstract:

To promote environment-friendly hydrogen generation through water electrolysis, high-performance, inexpensive electrocatalysts abundant in earth elements that do not depend on valuable metals and expensive materials are required. In the present work, the hydrothermal procedure was utilized to prepare CoS/MnO₂ composite and physical characterization methods were applied to study the crystal structure, shape and textual characteristics as well. The increased surface area and smaller crystallite size of CoS/MnO₂ composite demonstrate increased active sites for the oxygen evolution process. Nevertheless, electrocatalytic efficiency and stability for OER under basic medium have been demonstrated by different electrochemical studies. The produced catalyst revealed an overpotential η (261 mV), a low Tafel gradient (39 mV/dec) to acquire 10 mA/cm² current density (j) and low solution resistance (R_s) value (2.45 Ω) for CoS/MnO₂ composite than the distinct CoS and MnO₂. Additionally, the CoS/MnO₂ composite displayed outstanding stability, exhibiting an oxygen evolution reaction (OER) efficiency for over 50 h and maintaining a low reduction in activity even after 2500th CV cycles. These outcomes promote their capability in energy conversion as well as storage techniques.

Keywords: CoS/MnO2; OER; Electrocatalyst; Hydrothermal method; Stability

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-025-04340-w

Chemical Papers 79 (12) 8619–8631 (2025)