Electrochemical versatility synthesis of functional UiO-66 series heterogeneous membranes for highly efficient salinity gradient energy harvesting

Salinity gradient energy (SGE) harvesting from water has long been sought as a clean energy source. Commercial ion exchange membranes often face high energy barriers, inadequate ion transport ability, and chemical instability, thus displaying low power outputs. In this study, a series of continuous, flexible, zirconium-based metal–organic frameworks (Zr-MOFs) were synthesized on reduced graphene oxide membranes via electrochemical synthesis for highly efficient SGE harvesting are developed. The well-defined nanoscale channels and functional groups act as ionic filters and conductors, enhancing the ion selectivity for highly efficient SGE harvesting. Notably, the SO 3 H-UiO-66 membrane achieved a power density of 57.5 W/m −2 in neutral solution under a 1000-fold KCl concentration gradient, with a high K + transference number of 0.92, outperforming most reported membranes. Furthermore, the SO 3 H-UiO-66 membrane demonstrates a high output power density of 16.2 W/m −2 when tested with real seawater (Huang Hai) and domestic water, and is also effective in harvesting energy from wastewater, achieving a power density of 17.3 W/m −2 . This study opens new avenues for fabricating continuous Zr-MOF membranes as a platform for utilizing seawater and wastewater sources in SGE harvesting.