Photothermal-photocatalytic thin-layer flow system for synergistic treatment of wastewater

The integration of the photocatalytic effect into solar steam is highly desirable for addressing freshwater shortages and water pollution. Here, a ternary film structure for the adsorption and photothermal and photocatalytic treatment of wastewater was designed by combining the technique of self-assembled carbon nano paper with a nitrogen composite titanium dioxide (N-TiO2) deposited on the surface of carbon nanotubes (CNT) using polyvinylidene fluoride (PVDF) as a substrate. The photogeneration of reactive oxygen species can be promoted by rapid oxygen diffusion at the three-phase interface, whereas the interfacial photothermal effect promotes subsequent free radical reactions for the degradation of rhodamine B (93%). The freshwater evaporation rate is 1.35 kg·m−2·h−1 and the solar-to-water evaporation efficiency is 94%. Importantly, the N-TiO2/CNT/PVDF (N-TCP) film not only effectively resists mechanical damage from the environment and maintains structural integrity, but can also be made into a large film for outdoor experiments in a large solar energy conversion device to collect fresh water from polluted water and degrade organic dyes in source water simultaneously, opening the way for applications in energy conversion and storage.