Solar-Driven Interfacial Evaporator with a Self-Powered Detector Based on the Gr@Ti4O7:Eu3+,Yb3+ Fibrous Membrane

Interfacial evaporation is energy-efficient to alleviate the freshwater issues by utilizing the renewable and inexhaustible solar energy. Herein, a fibrous photothermal membrane of Gr@Ti4O7 doped with Yb3+ and Eu3+ was prepared by electrospinning, which presented high photothermal conversion efficiency (96.01%), an outstanding evaporation rate (1.82 kg·m–2·h–1), and a remarkable salt rejection rate (99.997%). These results demonstrated that the combination of Ti4O7, graphene, and rare earth elements achieved photothermal synergy and surpassed a majority of photothermal materials constructed by semiconductors. In addition, based on the biomimetic concept of unidirectional water transfer through trees, a self-monitoring function was achieved using asymmetric hydrophobic modification and an electrical signal of 802 mV was obtained. This work not merely provided valuable prospects for its application in seawater desalination but also discovered a new function for self-monitoring of the evaporation process.