High-Efficiency Photocatalytic H2O2 Production in a Dual Optical- and Membrane-Fiber System

Hydrogen peroxide (H2O2) is widely used for industrial applications. Currently, -,95% of H2O2 production employs the energy-and chemical-intensive anthraquinone oxidation process. Photocatalytic H2O2 production is an emerging alternative process. While advanced material discovery has been a primary focus of photocatalysis, breakthroughs in reactor designs capable of supporting novel materials are lacking. To enable low-energy and chemical-free photocatalytic production of H2O2, we integrated visible-light-emitting diodes (41 mW cm-2), optical fibers, and O2-delivering hollow-fiber membranes. A stable iron-based metal-organic framework photocatalyst (MIL-101(Fe)) activated by visible light was permanently affixed to the optical fiber, resulting in a uniform and high specific surface area (2650 m2 g-1). The combination of photocatalytic optical fiber and O2- permeable hollow-fiber membranes is a novel architecture for improving light utilization, photocatalyst reuse, and O2 supply. The H2O2 production rate in pure water was as high as 290 mM h-1 catalyst-g-1, which is as much as 60-fold greater than the best-reported values using photocatalytic slurries. The efficient delivery of light also achieved a low energy cost for H2O2 production (2.3 kWh kgH2OH2O2-1), and its production rate could be sustained for at least five repeated cycles (2 h per cycle). Energy-efficient H2O2 production without chemical inputs makes the dual-fiber system a more sustainable option for H2O2 production.