Theoretical and experimental insights into tungsten-induced structural and electronic modulations of CoSe2 for superior hydrogen evolution reaction

Abstract

Developing stable, highly efficient, and affordable electrocatalysts for water electrocatalysis is essential for advancing future energy solutions. The high cost and restricted availability of platinum group metal catalysts hinder the extensive use for renewable energy technology. As a result, improving the electrochemical properties of non-precious transition metal electrocatalysts is crucial for making renewable energy more cost-effective and accessible. In this study, we introduce a simple, straightforward approach to synthesizing tungsten-doped cobalt diselenide nanorods on carbon cloth (W–CoSe₂/CC) as an effective electrocatalyst for hydrogen evolution (HER) in an acidic solution. The W–CoSe₂/CC catalyst exhibited an overpotential of 41 mV and a low Tafel slope of 56 mV dec⁻¹ in 0.5 M H₂SO₄ to achieve a current density of 10 mA cm⁻². Furthermore, the W–CoSe₂/CC material demonstrated robust stability over 1000 cycles and maintained durability for 12 h in 0.5 M H₂SO₄. Density Functional Theory (DFT) computations have been employed to assess the impact of the dopant (W) employing differnet configurations on the crystalline structure of CoSe₂ (210). Site-1-W-CoSe₂-H at (0.01 eV) demonstrates the lowest Gibbs free energy (ΔG_H∗ = 0.01 eV) relative to other sites, supported by the maximum Bader charge (q = 4.12 |e|) and d-band centre value (εd = −1.21 eV), which evaluate the contribution of d-electrons. This straightforward fabrication approach and computational findings offer a new pathway for making innovative metal selenides for energy storage and conversion technologies.