Vacancy-Mediated Inverse Electron Transfer in Pt-Incorporated WO ₃ Nanosheets Enabling Chloride-Resistant and Precipitation-Free Seawater Hydrogen Production

The corrosive Cl – and precipitation-prone Ca 2+ /Mg 2+ ions in seawater severely compromise Pt-based hydrogen evolution reaction (HER) catalysts through sluggish kinetics, severe corrosion, and precipitate-induced active site passivation. Here, we present an inverse electron transfer design for Pt-incorporated vacancy-enhanced WO 3 nanosheets (Pt/v-WO 3 ) via an in situ photoreduction synthesis strategy. This approach increases the oxygen vacancy concentration in WO 3 for uniform Pt dispersion while reducing the work function of the WO 3 substrate for inverse electron transfer from WO 3 to Pt. The catalyst features an electron-rich Pt surface electrostatically repelling Cl –, an optimized d-band center optimizing H* adsorption, a self-regulated acidic microenvironment accelerating HER kinetics, and effective antiprecipitation properties preventing Ca 2+ /Mg 2+ deposits. Consequently, Pt/v-WO 3 delivers a 10.6-fold mass activity and a 10.7-fold turnover frequency than commercial Pt/C in simulated seawater, along with substantially enhanced durability. This work establishes a versatile strategic framework for designing corrosion-resistant Pt-based electrocatalysts for seawater hydrogen production.