Highly Efficient Solar-Driven Photothermal–Photocatalytic System Based on Supramolecular Iron Phthalocyanine Organic Polymer/CoFe₂O₄/Polydopamine for Wastewater Purification

Solar-driven evaporation is considered to be a sustainable water treatment technology that helps alleviate global water shortages. However, the secondary pollution caused by the accumulation of volatile organic compounds (VOCs) during the evaporation threatens water safety. Here, we designed a highly efficient 3D evaporator that combines supramolecular iron phthalocyanine organic polymer (PcOP-Fe) and CoFe₂O₄ (CFO) for simultaneous water evaporation and VOC degradation. It was demonstrated that the matched energy level of PcOP-Fe with CFO material can promote the photocarrier separation of CFO and further improve the photocatalytic activity. Meanwhile, the excellent photothermal performance of CFO can increase the local temperature to improve the transfer of photocarriers in PcOP-Fe and accelerate the reaction kinetics of VOC degradation simultaneously. Therefore, the designed evaporator exhibited an evaporation rate of 2.03 kg m^–2 h^–1 under 1 sun (1 kW m^–2) irradiation and a desalination efficiency over 99.7% for simulated seawater. Particularly, the evaporator delivers a high degradation efficiency ranging from 89.7% to 98.4% toward VOCs including phenol, N,N-dimethylformamide, and aniline. This work provides an effective evaporator with excellent photothermal and photocatalytic performance that can be applied in sewage treatment and seawater desalination.