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

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 lambda > 420 nm simulated sunlight efficiently boosts two-electron O-2 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.

Automated summary

This study reports the direct photosynthesis of hydrogen peroxide (H2O2) from seawater as a scalable and cost-effective solar fuel production method. The decoration of Au on Ni5P4 (Au@Ni5P4) was found to be an active and durable photocatalyst for non-sacrificial H2O2 synthesis from real seawater. Mechanism studies showed that the plasmonic Au decoration significantly suppressed charge-carrier recombination, and oxidation of halide ions in seawater assisted in H2O2 production.