A Self-floating hydrogel with Fe/C-doped MoS2 for simultaneous solar evaporation and purification of phenol.

Solar-driven interfacial evaporation offers a promising solution to freshwater scarcity and the practical application is often limited for complex wastewater containing salts and volatile organic compounds. To address these challenges, we developed an evaporator based on a self-floating polyvinyl alcohol/cellulose hydrogel integrated with a chitosan-derived Fe/C-MoS2 catalyst (Fe/C-MPC). The evaporator directed water transport via confined capillary action, thereby preventing salt accumulation and pore blockage. The expanded internal surface area further enhanced evaporation efficiency. Under 1-sun illumination, the system achieved a high evaporation rate of 5.78 kg m-2 h-1 in pure water with solar-to-vapor energy efficiency of 135%. Simultaneously, the Fe/C-MoS₂ catalyst, with its expanded interlayer spacing and abundant active sites, activated peroxymonosulfate through photothermal synergy and generated reactive radicals. This process efficiently degraded organic pollutants such as phenol. Localized heating at the Fe/C-MPC interface accelerated these catalytic reactions, while continuous water supply ensured effective transport of phenol to the active sites. In simulated wastewater containing 3.5 wt% NaCl and 5 mg L-1 phenol, the outdoor system maintained a phenol removal efficiency above 97.0% in distilled water and above 88.4% in bulk water under a sunny day. This work provides an integrated and sustainable strategy for the co-production of clean water and the purification of complex contaminated water, demonstrating strong potential for practical applications.