Lattice-matched metal/WN catalyst with highly oxygenophilic W sites for hydrogen production in seawater electrolyzer

Abstract

Designing efficient and durable hydrogen evolution reaction (HER) catalysts for seawater electrolysis is crucial for large-scale hydrogen production. Here, we introduce a theory-driven design of metal/WN electrocatalysts, with metal strongly coupled to lattice-matched WN. Theoretical calculations for Pt/WN reveal that W sites enhance H₂O adsorption/dissociation, optimizing Pt’s H binding. The prepared Pt/WN@CP nanorods can catalyze HER with low overpotentials of 107 and 113 mV at 500 mA cm⁻² in alkaline water/seawater, respectively, surpassing Pt/C. Extended calculations and experiments show that the optimized Ni/WN@CP-90 achieves an optimal ΔG_H* and overpotential of 219 mV at 500 mA cm⁻² in alkaline seawater, demonstrating the versatility of the WN support to promote HER activity. Notably, the anion exchange membrane water electrolyzer (AEMWE) constructed by Pt/WN@CP or Ni/WN@CP-90 with NiFe-LDH@NF demonstrates outstanding hydrogen production activity with excellent Faraday efficiency (∼100%) and durability (120 h), indicating the potential application of WN-supported catalysts for efficient and stable seawater electrolysis.