Photothermal Evaporator with MXene‐Regulated Fe 3+ /Fe 2+ Cycling via Ligand‐to‐Metal Charge Transfer for Solar Desalination and Wastewater Purification

ABSTRACT Combining interfacial solar evaporation and advanced oxidation provides a promising approach to ease global energy shortages and water pollution. However, fabricating bifunctional evaporators with excellent photothermal, catalytic and synergistic properties remains a tough technical challenge. In this work, a glass fiber membrane was adopted as the functional substrate to anchor MXene/MIL‐101(Fe) composites, thereby constructing a bifunctional evaporator (M/T‐GFM) integrating photothermal and catalytic capacities. As a photothermal component, MXene captures solar light and converts light energy into thermal energy to boost peroxymonosulfate (PMS) activation. Meanwhile, MXene acts as an electron donor to accelerate the Fe 3+ /Fe 2+ redox cycle within MIL‐101(Fe) via ligand‐to‐metal charge transfer (LMCT). It takes merely 20 min to degrade high‐concentration Reactive Blue 19 (R.B.19) of 100 mg L −1 completely and 84.32% of phenol in the condensed water, while the water evaporation rate hits 2.49 kg m −2 h −1 . Meanwhile, it exhibits excellent purification on actual dyeing and finishing wastewater. Density Functional Theory (DFT) calculations clarify PMS activation over Fe‐O‐Ti and Fe‐O sites. Relying on the synergistic mechanism where MXene‐mediated photothermal conversion and LMCT accelerate the Fe 3+ /Fe 2+ redox cycle, this study provides a new strategy for concurrent freshwater generation and wastewater remediation combining interfacial evaporation and a PMS based advanced oxidation process.