Fig. 1: Reactive coatings that purify using intermittent UV irradiation.
From: Photocatalytically reactive surfaces for simultaneous water harvesting and treatment
a, Schematic showing how a TiO2 nanocomposite coating can be activated by UV irradiation and remain reactive even in the dark, enabling the purification of water without continuous illumination from sources such as the Sun. e−, electron. b, Micrograph showing the TiO2-nanoparticle-laden coating (TiO2-PVB-PDMS). Scale bar, 200 nm. c,d, Image sequences showing how the reactive coatings TiO2-PVB-PDMS (c) and TiO2-EC-PDMS (d) can treat contaminated water droplets (C0 = 25 ppm methyl orange, dispensed droplet size V = 5 µl). Before these experiments, the coatings were irradiated with UV light, photocatalytically activating them; the coatings and droplets were not exposed to UV light thereafter. e, Plot of concentration versus time (C–t) (black line with circle symbols) for diesel dispersed in water. Here, the water–diesel solution was placed in a Petri dish (diameter 42 mm; liquid volume 100 µl) that was coated with the pre-activated TiO2-PVB-PDMS coating. (Appropriate control experiments were carried out to ensure that the emulsion was stable during the analysis—these are reported in Supplementary Fig. 2.) f, Plot of C versus t (blue line with square symbols) for a bisphenol A–water solution in a Petri dish coated with pre-activated TiO2-PVB-PDMS (liquid volume 3,000 µl). In e and f, each data point represents the average of n = 15 measurements (that is, five readings each for three separately prepared coating types) and the data are presented as the mean value ± standard deviation.
