Turning Sunlight and Seawater Into Energy: Photocatalytic Hydrogen Peroxide as a Green Fuel Carrier

Hydrogen peroxide (H₂O₂) is an emerging green energy carrier and a versatile oxidant. Its production, however, remains heavily reliant on the energy- and waste-intensive anthraquinone process. In contrary, photocatalysis provides a sustainable pathway for the preparation of H₂O₂ by utilizing oxygen (O₂) and water (H₂O) as feedstocks. In this aspect, since seawater is the most abundant water resource on the earth, utilization of seawater for the generation of H₂O₂ will have great potential in this field. However, the complex composition and high salt content of seawater pose significant challenges to the photocatalytic process, such as catalyst deactivation and interference with the reaction pathway. In this review article, we have summarized recent advances in the photocatalytic synthesis of H₂O₂ directly from seawater. We have initially introduced the basic principle of photocatalytic reaction and the interaction between the components in seawater and the photocatalyst. Then, according to the different types of photocatalysts, we have discussed the research progress, their advantages, and limitations in the synthesis of H₂O₂. Finally, we have provided the current technological bottlenecks and foreseen future research directions. In summary, this review article will provide a comprehensive understanding of the generation of H₂O₂ directly from seawater.