Gold–nickel phosphide heterostructures for efficient photocatalytic hydrogen peroxide production from real seawater

Abstract

Direct hydrogen peroxide (H₂O₂) photosynthesis from Earth-abundant seawater provides an attractive path for scalable and cost-effective solar fuel production for the future, but the sluggish half-reaction of water oxidation and unpropitious rapid charge recombination of photocatalysts impede the solar-to-H₂O₂ conversion efficiency. We report here Au covalently anchored on Ni₅P₄ (Au@Ni₅P₄) as an active and durable photocatalyst for non-sacrificial H₂O₂ synthesis from real seawater. Au@Ni₅P₄ photoirradiated by λ > 420 nm simulated sunlight efficiently boosts two-electron O₂ reduction and four-electron water oxidation, yielding a high solar-to-H₂O₂ conversion efficiency of 0.29%, along with excellent stability. Mechanism studies reveal that the decoration of plasmonic Au significantly suppresses the charge-carrier recombination and the oxidation of halide ions in seawater assists in the production of H₂O₂. We envision that this study will allow the future design of more efficient plasmon-mediated photocatalysts and advance their applicability for H₂O₂ production from seawater.