Interface-engineered Ni₃S₂/WO₃ heterostructures bridging Volmer/Tafel processes via hydrogen spillover for enhanced...

Designing high-performance catalysts for the hydrogen evolution reaction (HER) is essential for large-scale hydrogen production via anion exchange membrane water electrolysis (AEMWE), yet the high energy barrier for water dissociation remains a great challenge. Here, we present a heterostructure catalyst composed of crystalline Ni₃S₂ and amorphous WO₃, designed with distinct functional domains through interface engineering. Both experimental and theoretical results show that WO₃ promotes electron transfer to Ni sites, stabilizing them in a lower oxidation state, which shifts the d-band center upward, reducing the water dissociation barrier and facilitating *H generation. These *H species then spillover to adjacent sites, altering the HER pathway and enhancing catalytic performance. As a result, the Ni₃S₂/WO₃ catalyst achieves an overpotential of 237 mV at 500 mA cm^-2, and the corresponding AEMWE system operates at 500 mA cm^-2 with a cell voltage of 1.88 V, maintaining stable performance for over 500 h. These findings provide valuable insights into the design of efficient heterostructure catalysts for AEMWE applications.