The development of high-performance, binder-free electrocatalysts is essential for advancing sustainable energy conversion technologies such as water electrolysis. In this study, walnut kernel-like iron-cobalt-nickel sulfide nanosheets (FeCoNiSx/NF) were synthesized directly on nickel foam via a simple room-temperature sulfuration process using sodium thiosulfate pentahydrate as the sulfur source. This method avoids high temperatures, pressure, or complex post-treatment steps, enabling rapid and scalable fabrication of well-defined nanostructures without the need for binders. The resulting catalyst exhibits a unique hierarchical architecture composed of ultrathin, crumpled nanosheets with abundant exposed edges and internal porosity, which significantly enhances the electrochemically active surface area.
Electrochemical evaluation in 1.0 M KOH reveals exceptional oxygen evolution reaction (OER) performance. The FeCoNiSx/NF electrode achieves current densities of 10 mA cm⁻² and 50 mA cm⁻² at overpotentials of just 231 mV and 268 mV, respectively—among the lowest reported values for nonprecious metal systems. The Tafel slope of 55 mV dec⁻¹ indicates favorable reaction kinetics, suggesting that the rate-determining step involves the adsorption of OH⁻ species during the formation of MOH intermediates. Electrochemical impedance spectroscopy confirms a low charge transfer resistance (3.0 Ω), while cyclic voltammetry analysis shows a double-layer capacitance of 58.6 mF cm⁻², indicating a large accessible surface area and high density of active sites.
Stability is a critical factor for practical application, and FeCoNiSx/NF demonstrates remarkable durability. Chronopotentiometric measurements show negligible potential drift over 24 hours at 50 mA cm⁻².345630-40-2 medchemexpress After 1000 continuous cyclic voltammetry scans, the LSV curve remains nearly unchanged, confirming excellent structural and electrochemical stability. Post-test characterization by SEM, TEM, XPS, and XRD reveals no significant morphological or chemical degradation. The nanosheet morphology is preserved, and the core Fe-Co-Ni-S composition remains intact, with only minor oxidation of sulfur observed. These findings highlight the robustness of the direct growth strategy on conductive NF substrates.
When integrated into an overall water electrolysis cell paired with Pt/C on NF as the cathode, FeCoNiSx/NF delivers a cell voltage of 1.1365970-03-1 IUPAC Name 52 V at 10 mA cm⁻²—lower than that of IrO₂/Pt/C (1.PMID:30057217 57 V). The system maintains stable operation for up to 80 hours under constant current, demonstrating strong resistance to degradation. Faradaic efficiency approaches 100%, verified by quantitative O₂ detection, confirming that O₂ evolution is the primary reaction pathway.
The enhanced catalytic activity arises from synergistic effects among Fe, Co, and Ni ions, which modulate the electronic structure and optimize the adsorption energy of oxygen-containing intermediates. The porous, sheet-like morphology promotes efficient mass transport and facilitates rapid release of gas bubbles, reducing local overpotential. Furthermore, the direct integration with NF eliminates interfacial resistance and prevents catalyst detachment, enhancing both conductivity and mechanical stability.
This work presents a rational design strategy for developing high-performance, binder-free electrocatalysts based on transition metal sulfides. The FeCoNiSx/NF system combines earth-abundant elements, facile synthesis, superior activity, and long-term stability, making it a highly promising candidate for next-generation green hydrogen production technologies.MedChemExpress (MCE) offers a wide range of high-quality research chemicals and biochemicals (novel life-science reagents, reference compounds and natural compounds) for scientific use. We have professionally experienced and friendly staff to meet your needs. We are a competent and trustworthy partner for your research and scientific projects.Related websites: https://www.medchemexpress.com
