Xuanting Li, Jinchi Li, Xinrong Huang, Qian Chen, Xinyu Li, Hongbing Wang, Jiang Gong, Ran Niu, Xiaoke Li*

Active intermediate water-mediated kinetic promotion for synergistic solar evaporation and photocatalytic mineralization

Chemical Engineering Journal (2026) Accept.

Integrating photocatalytic decontamination with solar interfacial evaporation (SIE) offers a sustainable solution for the water-energy-environment nexus, yet high efficiency is hindered by trade-offs between thermal localization-induced charge carrier recombination and evaporation-driven solute accumulation. Here, the intermediate water-mediated strategy resolves these thermodynamic and kinetic conflicts by employing a layered porous double-network hydrogel (PCF) embedded with NH2-MIL-101(Fe)/graphene oxide (GO). The oxygen-rich polyvinyl alcohol (PVA) and carbonylated cellulose nanofibrils (CNF) skeleton reconstructs the hydrogen-bonding network within confined domains, yielding a high intermediate-to-free water ratio (1.295). This distinct water state functions dualistically: thermodynamically, it substantially reduces the equivalent vaporization enthalpy to 869.3 J g-1. Kinetically, it serves as a pre-activated reactant that lowers the energy barrier for hydroxyl radical (·OH) generation over the NH2-MIL-101(Fe)/GO active sites. Consequently, the evaporation rate of PCF is 3.29 kg m-2 h-1 under one sunlight, and the degradation efficiency of PCF for broad-spectrum organic pollutants (RHB, MB, TC) is more than 90%. Furthermore, its vasculature-mimicking architecture ensures rapid salt backflow, achieving zero salt crystallization in 5 wt.% brine during long-term operation. This study highlights water state regulation in bridging photothermal and photocatalytic processes, providing a paradigm for designing multifunctional materials for complex wastewater treatment.