Controllable synthesis of N/Co-doped carbon from metal–organic frameworks for integrated solar vapor generation and advanced oxidation processes

Abstract

Interfacial solar-driven vapor generation is considered to be a promising technology to produce freshwater from non-potable water. However, when the source water contains organic pollutants, the solar-driven water evaporation process might worsen the pollution of the source water. Herein, we construct a bifunctional interfacial solar-driven evaporator by facilely dip-coating MOF-derived N/Co-doped carbon on cotton cloth, which can simultaneously realize freshwater production by solar-driven evaporation and the degradation of organic pollutants. The derived carbon hybrid is composed of wrinkled bamboo-like N-doped carbon tubes and embedded Co nanoparticles, which not only contribute to efficient sunlight absorption and photothermal conversion but also provide abundant catalytic sites for visible light-driven peroxymonosulfate (PMS) activation to produce diverse reactive oxygen species (ROS). In another aspect, the cotton cloth consisting of interlaced cellulosic fibers offers hydrophilic channels for fast water transport and decreases the water evaporation enthalpy to accelerate evaporation. As a result, the bifunctional evaporator presents a notably high evaporation rate of 2.2 kg m⁻² h⁻¹ under 1 kW m⁻² illumination, securing one of the best values among solar evaporators. More importantly, it displays excellent performance in PMS activation under visible light irradiation to produce plenty of ROS for the catalytic degradation of various toxic organic pollutants in source water (e.g., its Congo red degradation efficiency was 96.6% within 90 min). The bifunctional solar evaporator provides an ingenious way to handle the issues of global freshwater scarcity and water contamination via the marriage of interfacial solar-driven evaporation technology and advanced oxidation processes.