Engineering Interfacial Built-In Electric Fields via Work Function Matching Enables Photocoupled Osmotic Energy...

Osmotic energy conversion offers a sustainable route to harvest electricity from salinity gradients. Beyond natural seawater/riverwater systems, saline waste streams rich in dissolved ions and persistent organic pollutants remain an underutilized resource for simultaneous energy recovery and remediation. Here, we report an asymmetric MoS₂/oxygen-doped ZIF-8 membrane (MS-ZIF-A) that incorporates a built-in electric field (IEF) to accelerate selective ion transport and enhance osmotic energy conversion. Work function matching between the functional layers optimizes interfacial band alignment, strengthening the internal driving force for ion migration and enabling a peak power density of 9.4 W m^-2 under a 50-fold NaCl salinity gradient. In simulated industrial wastewater containing NaCl and RhB, the membrane delivers power densities of up to 30 W m^-2 while concurrently degrading organic pollutants. These results establish work function engineering as an effective strategy to construct interfacial IEF in asymmetric membranes, providing a general design principle for high-performance blue-energy devices and offering a promising route toward energy-positive treatment of saline wastewater.