Synthesis and characterizations of SrMnO3 with rGO nanosheets (SMO-rGO) in energy-related applications

Abstract

A crucial aspect of an oxygen evolution reaction is the improvement of electrocatalysts in an alkaline solution. Owing to their highly intrinsic activity and porous nature, perovskites (ABO₃) served as potential catalysts for OER. Transition-metal-oxides such as SrO₂, MnO₂, FeO, Co₃O₄ and NiO are considered potential catalysts for OER; strontium and manganese base oxides are efficient and have low cost. These catalysts have gained massive attention because of their structure, morphology and polyvalency. Herein, the crystalline perovskite SrMnO₃-rGO was fabricated using the hydrothermal method and analyzed using different physical and electrochemical characterizations. Different physical techniques were applied to study crystal structure, morphology and lattice vibration. The scanning electron microscopic analysis confirmed the homogeneous and small-sized structure of pristine SrMnO₃ and SrMnO₃-rGO composite. Moreover, composite showed a greater surface area (68 m² g⁻¹) according to the Brunauer Emmett Teller analysis. Then, the developed material was observed to determine stability, Tafel slope and overpotential. Further, the electrochemical characteristics of nickel foam (NF) are also analyzed which displays an overpotential of 378 mV and a Tafel value (80 mV dec⁻¹). In comparison, the prepared SrMnO₃-rGO composite showed an overpotential (198 mV) at standard current density (10 mA cm⁻²) and Tafel plot (37 mV dec⁻¹) with higher durability (30 hours) at 4000^th CV cycles. EIS was used to analyze the material’s resistance, which showed minimum R_ct (0.3 Ω) for composite. The present study expands perovskite-oxides with rGO performance as a catalyst, making it highly efficient for OER electrocatalysts. It can be applied at an industrial scale in the future.

Graphical Abstract