Synergistic Optimization of WP/WS₂ Electrocatalyst by P/S Dual Vacancies and Heterojunctions for Hydrogen Evolution and Zn–H₂O Batteries

Vacancy engineering is widely used to boost the hydrogen evolution reaction (HER) performance. However, dual-vacancy systems are more complex than mono-vacancy structures and remain underexplored. Key challenges involve developing emerging dual-vacancy catalysts, understanding their synergistic effects, and expanding their applications. Here, P/S dual vacancies were fabricated and coupled to heterostructures to improve HER performance. The as-synthesized WP/WS₂-H heterostructures rich in P/S dual vacancies exhibit overpotentials of 175 and 170 mV at a current density of 10 mA cm^-2 within 1 M KOH and 0.5 M H₂SO₄, respectively. The ability of P/S dual vacancies to promote HER activity of WP/WS₂-H heterostructures is obviously higher than those of P and S mono-vacancy in WP-H and WS₂-H. The heterojunctions of WP/WS₂-H optimize the charge distribution, enhance the charge transfer rate, and increase the number of electrochemically active sites, thereby improving HER activities. Moreover, the as-fabricated Zn-H₂O battery with WP/WS₂-H as the cathode presents a maximum power density of up to 6.3 mW cm^-2 and a stable discharge capacity of 69 h. This research not only provides a vigorous strategy for fabricating new dual-vacancy catalyst systems but also illustrates a synergistic effect and expands their application.