Synergistic enhanced solar-driven water purification and CO₂ reduction via photothermal catalytic membrane distillation

Energy and freshwater, as natural and important strategic resources, are the lifeblood and basic security of economic and social development. Freshwater production consumes vast energy, and vice versa. It is rare and still a significant challenge in the rational design of implementation for efficient clean water and chemical fuel production via solar-thermal technology, reconciling the water-energy contradiction. Herein, we demonstrated a new double-stage solar catalytic membrane distillation (DSCMD) system, integrating photocatalyst into the photothermic electrospun film that is imparted with the water feeding, photothermic conversion and photocatalysis functions, which simultaneously realized the stable freshwater and enhanced clean fuels production. The photothermal/catalytic materials synergistically harvest photons for localized heat generation, which also acts on catalytically active sites to enhance the yield of vapor and CO, so as to maximize the utilization of solar energy. As a result, the overall freshwater collection rate of 1.45 kg m^-2h⁻¹ with the solar-to-water efficiency of up to 90.6 % and enhanced CO evolution rate of 21.29 μmol g_cat⁻¹ h⁻¹ from CO₂ photoreduction are achieved by more effective vapor transportation and latent heat recovery, superior to the traditional photothermal membrane distillation systems, providing an alternative opportunity for sustainably alleviating the freshwater and energy shortage.