Gradient Titanium Oxide Nanowire Film: a Multifunctional Solar Energy Utilization Platform for High-Salinity Organic Sewage Treatment

The treatment of high salt organic sewage is considered to be a high energy consumption process, and it is difficult to degrade organic matter and separate salt and water simultaneously. In this study, a gradient structure titanium oxide nanowire film is developed, which can realize the thorough treatment of sewage under sunlight. Among the film, part TiO 2– x has enhanced photocatalytic properties and can completely degrade 0.02 g·L –1 methylene blue in 90 min under 2 sun. Part Ti n O 2 n –1 has excellent photothermal conversion efficiency and can achieve 1.833 kg·m –2 ·h –1 water evaporation rate at 1 sun. Through the special structure design, salt positioning crystallization can be realized to ensure the film’s stable operation for a long time. The gradient hydrophilicity of the film ensures adequate and rapid water transfer, while the water flow can induce a significant hydrovoltaic effect. The measured V OC is positively correlated with light intensity and photothermal area and corresponds to the water evaporation rate.