Bridging Materials Innovation with an Efficient Photocatalyst-Enabled Optical Fiber Reactor for HO Production.

Hydrogen peroxide (HO) is a green oxidant widely used in water treatment and sustainable chemistry. Although many advanced materials exist for photo- and electrocatalytic production, HO output and stability depend on reactor design and water quality. This study explores a scalable photochemical system employing bismuth vanadate-coated polymeric optical fibers (POF-BVO) illuminated by 440 nm LEDs. A single 20 cm, 3 mm diameter fiber generates HO at 4.3 mg HO h (430 mg HO g h), with enhanced rates achieved using bundled fibers. The bundled configuration increases fiber packing density in the reactor to >120 m m, tripling that of flat-plate photocatalytic reactors. High HO production is achieved using oxygen-permeable hollow-fiber membranes to deliver pure O or air. The system performs consistently across pH 4-9 and in tap water, wastewater, or seawater. Phosphate ions improve HO stability, resulting in higher concentrations. Over 21 days of continuous operation, the system produces >6 g L of HO with minimal performance degradation. Energy analysis reveals a 2-30x reduction in energy use compared to traditional slurry-based photocatalytic systems, with a three-fiber bundle reaching 27 kWh kg─comparable to electrochemical processes. These results demonstrate the potential of the POF-BVO platform as an energy-efficient and modular solution for decentralized HO production.