Marigold-flower-like MoS2 nanosheet assemblies for enhanced alkaline hydrogen evolution

Abstract

The development of efficient, cost-effective, and noble-metal-free electrocatalysts is critical for sustainable hydrogen production via water splitting. Herein, hierarchical MoS₂ nanosheets were synthesized through a facile hydrothermal method, producing a marigold flower-like morphology with abundant exposed edge sites. Structural and compositional analyses using XRD, Raman, XPS, SEM, and BET confirmed the formation of crystalline, layered, and mesoporous MoS₂. Electrochemical evaluation in 1.0 M KOH revealed excellent hydrogen evolution reaction (HER) activity, with a low overpotential of 180 mV at 10 mA cm⁻², a Tafel slope of 122.3 mV dec⁻¹, and reduced charge-transfer resistance, highlighting efficient electron transport. Chronoamperometric measurements demonstrated outstanding long-term stability over 10 h. The combination of tailored morphology, high surface area, and favorable electronic structure establishes hydrothermally synthesized MoS₂ as a promising and practical electrocatalyst for sustainable hydrogen generation.