Sustainable porous evaporators constructed via Pickering emulsion templating of photothermal zein–metal–phenolic hybrid particles for solar desalination

Freshwater scarcity represents a critical global crisis, necessitating advanced sustainable water purification technologies. While solar-driven interfacial evaporation (SDIE) emerges as an energy-efficient solution, conventional photothermal conversion materials often rely on energy-intensive synthesis or non-renewable resources, compromising their environmental sustainability. Herein, we present a sustainable synthesis paradigm that harnesses zein, a plant-derived biological macromolecule, to develop the metal-phenolic networks (MPNs)-reinforced porous architecture for SDIE system. Zein nanoparticles were functionalized through coordination-driven self-assembly with Fe 3+ and proanthocyanidin, forming ZP-PA/Fe 3+ hybrid particles that serve dually as Pickering emulsion stabilizers and photothermal agents. These particles precisely integrated into a poly(vinyl alcohol) matrix via Pickering emulsion templating, yielding a hierarchical porous scaffold. The optimized P-ZF evaporator achieved an evaporation rate of 2.24 kg·m −2 ·h −1 under 1 sun—exceeding most reported MPN-coated systems (typically ~1.43–1.85 kg·m −2 ·h −1 )—while also demonstrating long-term operational stability, retaining ~90 % efficiency after two years of ambient storage. This study not only validates MPNs-functionalized porous platforms as high-efficiency solar water evaporators but also provides a green synthesis protocol, circumventing the sustainability limitations of conventional synthetic routes.