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

Hydrogen peroxide (H 2 O 2 ) is widely used for industrial applications. Currently, ∼95% of H 2 O 2 production employs the energy- and chemical-intensive anthraquinone oxidation process. Photocatalytic H 2 O 2 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 H 2 O 2, we integrated visible-light-emitting diodes (41 mW cm –2 ), optical fibers, and O 2 -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 m 2 g –1 ). The combination of photocatalytic optical fiber and O 2 -permeable hollow-fiber membranes is a novel architecture for improving light utilization, photocatalyst reuse, and O 2 supply. The H 2 O 2 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 H 2 O 2 production (2.3 kWh kgH 2 O H 2 O 2 –1 ), and its production rate could be sustained for at least five repeated cycles (2 h per cycle). Energy-efficient H 2 O 2 production without chemical inputs makes the dual-fiber system a more sustainable option for H 2 O 2 production.