Enhancing the Hydrogen Evolution Performance of Tungsten Diphosphide on Carbon Fiber through Ruthenium Modification

Hydrogen-based energy systems hold promise for sustainable development and carbon neutrality, minimizing environmental impact with electrolysis as the preferred fossil-fuel-free hydrogen generation method. Effective electrocatalysts are required to reduce energy consumption and improve kinetics, given the need for additional voltage (overpotential, η) despite the theoretical water splitting potential of 1.23 V. To date, platinum has been acknowledged as the most effective but expensive hydrogen evolution reaction (HER) catalyst. Hence, we introduce a cost-effective (∼2-fold cheaper) ruthenium-modified tungsten diphosphide (Ru/WP2) catalyst on carbon fiber for HER in ∼0.5 M H2SO4, with η ≈ 34 mV at -10 mA cm-2 which can be comparable (only ∼2-fold higher) to benchmark Pt/C (η ≈ 17 mV). The HER performance of WP2 can be enhanced through the modification of ruthenium, as indicated by the electrochemical characterizations. Considering the Tafel value of ∼40 ± 0.2 mV dec-1, it can be inferred that Ru/WP2 follows the Volmer-Heyrovsky reaction pathway for hydrogen generation. Furthermore, the Faradaic efficiency estimation indicates that Ru/WP2 demonstrates a minimal loss of electrons during the electrochemical reaction with an estimated value of ∼98.7 ± 1.4%. Therefore, this study could emphasize the potential of the Ru/WP2 electrode in advancing sustainable hydrogen production through water splitting.

Insights into the Effect of Sulfur Incorporation into Tungsten Diphosphide for Improved Hydrogen Evolution Reaction

Exploring the highly active and stable nonprecious metal electrocatalysts is particularly important for the advancement of water electrolysis, whereas it remains a challenge to efficiently improve the intrinsic electrocatalytic activity. Herein, we reasonably constructed a self-supporting nanosheet array material with sulfur incorporated into WP₂. Because of the tunability of electronic configuration and the formation of partial metal phase sulfides, the optimized catalyst exhibits a low overpotential of 115 mV at 10 mA cm^-2, along with superb durability over 24 h in acidic media. Furthermore, theoretical calculations reveal that sulfur substitution effectively manipulates the local electronic configuration of WP₂, which reduces the interaction between the catalyst surface and hydrogen atoms, thus improving the intrinsic activity of the hydrogen evolution reaction. This work provides valuable insight into the rational fabrication of highly efficient flexible electrode materials based on resourceful electrocatalysts for electrochemical water splitting.