Oxygen vacancy-engineered black TiO2/defective g-C3N4 composite sponge hydrogels for full-spectrum solar evaporation and tylosin degradation

Addressing water scarcity and pollution in underdeveloped regions requires safe water production from inferior sources. Solar-driven interfacial evaporation (SDIE) coupled with photocatalysis offers great potential for this challenge. Herein, a dual-functional composite (BTG@MS) was fabricated by immobilizing oxygen vacancy- and Ti(III)-rich black TiO 2 /defective g-C 3 N 4 (BTG) on melamine sponge (MS) hydrogel. The composite broadens light absorption to 300–1200 nm (80.7% average absorption efficiency) and forms a type-II heterojunction, facilitating charge separation and reactive oxygen species (ROS) generation. Benefiting from MS’s hierarchical water transport pathways and BTG’s enhanced solar utilization, BTG@MS exhibits outstanding dual performance under one-sun illumination (1 kW/m 2 ), an evaporation rate of 1.26 kg/(m 2 ·h) (74.3% photothermal efficiency) and 84.5% tylosin (TYL) degradation efficiency. It also shows salt tolerance and effectiveness in purifying four types of water sources, producing clean water meeting WHO standards. This work presents an innovative strategy integrating photothermal evaporation and photocatalysis, promising practical application in tackling the water crisis in underdeveloped regions.