Janus-interface engineering enhances hydrogel integrated with ZIF-8@Co9S8 composite featuring concave pyramid patterns for efficient solar-driven water purification

• • Achieves 96% solar absorption across 200–2500 nm via concave pyramid light-trapping architecture, enabling broadband photothermal conversion critical for efficient solar steam generation under diffuse sunlight. • • Demonstrates an evaporation rate of 2.69 kg m−2 h−1 and solar-to-vapor efficiency of 98.15% under one-sun illumination (1 kW m−2), surpassing many conventional ISSG systems and approaching theoretical limits. • • Sustains stable performance for 11 hours in 3.5 wt% brine without observable salt crystallization, attributed to Janus asymmetric wettability (hydrophobic ZIF-8 top, hydrophilic PVA bottom), addressing a key operational bottleneck for long-term desalination. • • Outdoor tests produced 14.28 kg m−2 of freshwater in 10 hours of natural sunlight, and the device removed organic dyes and reduced ion concentrations to below WHO drinking-water limits, validating practical applicability for real-world water purification.