Self-floating wood membrane with a gas-liquid-solid triphase interface for photocatalytic H2O2 production and sustainable water purification.

Sustainable production of H2O2 coupled with pollutant removal is highly desirable for water treatment but remains challenged by inefficient oxygen supply and interfacial reaction limitations in conventional slurry systems. Here, a self-floating RP/wood membrane is developed to regulate interfacial transport and enable photocatalytic H2O2 production at the air-water interface. Resorcinol-formaldehyde@polypyrrole (RF@PPy, denoted as RP) were immobilized onto a wood scaffold through PVDF-assisted assembly, forming an RP/wood membrane with hierarchical porosity and asymmetric wettability. The aligned capillary channels of the wood substrate provide continuous water transport, while the catalytic layer remains exposed to air, establishing a stable gas-liquid-solid triphase interface that facilitates oxygen supply and photon utilization. As a result, the system exhibits environmental adaptability, with optimal H2O2 production under mildly acidic conditions (pH 5.81) and a high generation rate of 657.10 μM·h-1. After 14 days of immersion, the rate remains at 575.2 μM·h-1, indicating good structural stability. Notably, continuous H2O2 accumulation is achieved under natural sunlight irradiation, demonstrating its applicability under real outdoor conditions. The generated H2O2 can be directly utilized for pollutant degradation, achieving rapid pollutants removal under visible light and natural sunlight. The membrane maintains high reusability, with negligible catalyst loss after several cycles due to effective immobilization. This work provides a scalable and energy-efficient strategy for integrating solar energy utilization, green oxidant generation, and water purification, highlighting the potential of biomass-derived materials for sustainable environmental remediation.