Hierarchically structured CoAl-LDH derived hybrid membrane for synergistic solar-driven water purification and photocatalytic CO2 reduction

The increasing global demand for freshwater and clean energy necessitates innovative solutions that address both resource scarcity and environmental challenges. Herein, we present a 2D sandwich-like hybrid membrane, composed of bacterial cellulose (BC) and calcined CoAl-LDH nanosheets (CAL-T), fabricated via a layer-by-layer deposition strategy. This multifunctional membrane synergistically integrates photothermal evaporation and photocatalytic CO 2 reduction, leveraging the porous structure and narrow bandgap (1.37 eV) of CAL-T to enhance solar absorption and energy conversion. Furthermore, the BC matrix facilitates efficient water transport and mechanical stability, ensuring long-term operational performance. Under 1 kW ∙ m −2 solar irradiance, the BC/CAL-650 membrane achieves a water evaporation rate of 1.36 kg ∙ m −2 ∙ h −1 , surpassing most reported 2D evaporators, and a CO evolution rate of 8.78 μmol ∙ g −1 ∙ h −1 , significantly outperforming conventional photocatalysts. Furthermore, the BC matrix facilitates efficient water transport and mechanical robustness, ensuring long-term operational performance. These dual-functional capabilities, coupled with low-cost fabrication (~$0.0041 per membrane), demonstrate the membrane's superiority and practical potential in integrated solar-driven water purification and solar-to-fuel conversion. This work establishes a versatile platform for advancing next-generation hybrid materials to mitigate water scarcity and climate change challenges.