Ternary Copper Iron Sulfide Microflowers Anchored on Reduced Graphene Oxide for Water Splitting

Abstract

Transition metal sulfides are widely employed as bifunctional electrocatalysts owing to their unique structural features, well-off active sites, and modifiable electronic and mechanical properties. Herein, we have synthesized highly efficient ternary copper iron sulfide (CuFeS 2 )/reduced graphene oxide (rGO) composites via a hydrothermal approach for an overall water splitting process. The tetragonal structure of CuFeS 2 microflowers anchored on rGO sheets is identified by using Xray analysis and compared with standard Joint Committee on Powder Diffraction Standards (JCPDS) #35-752. In Raman spectra, the existence of two bands D (defects) and G (graphitic) confirms the presence of the rGO composite with CuFeS 2, and the ratio of D and G band (I D /I G ) is observed to be 1.18. The morphological analysis using scanning electron microscopy and transmission electron microscopy substantiates the formation of microflowers with rGO sheets. The elemental composition of CuFeS 2 /rGO was analyzed by energy-dispersive X-ray analysis, which demonstrated a weight percentage of various compositions of Cu (18.07%), Fe (11.32%), S (13.88%), and C (56.74%). Moreover, the CuFeS 2 /rGO composites exhibited a high surface area, pore volume, and diameter of 50.352 m 2 /g, 0.162 cc/g, and 2.471 nm, respectively. The fabricated electrodes were examined by using electrochemical characterization. The obtained results clearly showed low overpotential and low Tafel slope values in both the oxygen evolution reaction (OER) (176 mV and 216 mV/dec) and hydrogen evolution reaction (HER) (153 mV and 150 mV/dec) processes. In addition, the fabricated composite exhibited low 1.59 V cell voltages for an overall water splitting process with more excellent stability, and it showed a faradaic efficiency of 97.8% for H 2 and 95.5% for O 2 . Therefore, the composite of rGO in ternary metal sulfide plays a predominant role in improving the electrocatalytic activity of the material, and the CuFeS 2 /rGO composite emerges as a promising electrode for the water splitting process.

Synthesis and electrochemical application of two-dimensional manganese-based materials

“…TMOs notable for generating a plethora of oxygen vacancies upon interaction with reactants, possess abundant active sites that significantly benefit catalytic reactions and offer high energy density. 92 Manganese oxides, known for their diverse valence states, valence electron configurations, and high specific capacitance, find extensive applications in catalysis, electrode materials, supercapacitors, and more. 12,55,93 As a unique class of nanomaterials, 2D manganese oxides exhibit distinct physicochemical properties and broad application prospects, demonstrating significant advantages in energy storage, catalysis, sensing, electronics, and optoelectronics: 94–98…”