Rationally designing of Co-WS catalysts with optimized electronic structure to enhance hydrogen evolution reaction.

Designing and developing cost-effective, high-performance catalysts for hydrogen evolution reaction (HER) is crucial for advancing hydrogen production technology. Tungsten-based sulfides (WS) exhibit great potential as efficient HER catalysts, however, the activity is limited by the larger energy required for water dissociation under alkaline conditions. Herein, we adopt a top-down strategy to construct heterostructure Co-WS nanofiber catalysts. The experimental results and theoretical simulations unveil that the work functions-induced built-in electric field at the interface of Co-WS catalysts facilitates the electron transfer from Co to WS, significantly reducing water dissociation energy and optimizing the Gibbs free energy of the entire reaction step for HER. Besides, the self-supported catalysts of Co-WS nanoparticles confining 1D nanofibers exhibit an increased number of active sites. As expected, the heterostructure Co-WS catalysts exhibit remarkable HER activity with an overpotential of 113 mV to reach 10 mA cm and stability with 30 h catalyzing at 23 mA cm. This work can provide an avenue for designing highly efficient catalysts applicable to the field of energy storage and conversion.