Solar-driven H2O2 production via cooperative auto- and photocatalytic oxidation in fine-tuned reaction media

Abstract

Solar photocatalysis has emerged as a sustainable route to produce H₂O₂; however, the structural design of photocatalysts makes them expensive, limiting their practical applications. Inspired by the industrial anthraquinone process, we developed a new reaction design for solar H₂O₂ production using an organic working solution (OWS) comprising aryl alcohols and a metal-free polymeric photocatalyst. The synergistic auto- and photocatalytic oxidation of aryl alcohols in the OWS allowed for the quantitative generation of H₂O₂ by counter O₂ reduction. The fine modulation of the OWS with water enhanced the photocatalytic route, resulting in an unprecedented H₂O₂ production rate of 46.9 mmol h⁻¹ g⁻¹ with a solar-to-chemical conversion efficiency of 1.1% under simulated sunlight. Pure H₂O₂ was obtained after extraction and purification by membrane filtration, and was directly used in large-scale water purification as a proof of concept. This study demonstrates the importance of reaction design in photocatalytic applications and will promote future advancements in green, solar-driven H₂O₂ production.