MXene Membrane as Multifunctional Interface for Vapor Splitting via Photothermal-Catalytic Membrane Distillation

Advancements in solar-driven processes are fundamentally transforming the production of freshwater and energy into a more sustainable manner. Realizing such potential requires developing highly efficient solar responsive materials and advanced solar systems. Here, an MXene-based membrane is reported as a multifunctional interface capable of simultaneously producing freshwater and hydrogen through a strategically designed photothermal-catalytic sweeping gas membrane distillation (PTC-SGMD) system. By leveraging membrane interface engineering, the innovative design integrates solar evaporation, vapor transportation, and vapor splitting within a single membrane. Unlike conventional liquid-solid systems, this liquid-solid-gas configuration overcomes photocatalyst leaching, interfacial heat loss, and inefficient mass transfer. The multifunctional membrane exhibits enhanced solar absorption and optimal permeability, enabling the MXene-photocatalyst composite to achieve efficient photocatalytic vapor splitting. Remarkably, the optimized SrTiO₃/MX@PVDF membrane achieves a simultaneous water flux of 2.37 kg m^-2h^-1 and hydrogen production of 947.8 µmol m^-2h^-1 under 1 sun irradiation. The PTC-SGMD system demonstrates total solar efficiency of 92.305% with outstanding stability over 72 h of continuous operation. This innovative approach offers a scalable solution to global water scarcity and energy challenges.