Design Synthesis Of TiO₂Composites And Their Macroscale Assembly

As an important semiconductor material, TiO2is poisonless and harmless, havinggood chemical stability and good photocatalytic properties. It can product H2fromwater under UV light, and have good photocatalytic degradation ability to the organicand inorganic pollutants in raw water. In this paper, we designed synthesis of compositewith nano-TiO2, and increased the range of spectral absorption and good adsorptioncapacity. Above all, the results were briefly described as follows:1. By taking advantage of the structural affinity between bismuth oxohalide andTiO2, we successfully prepare a family of hybrid frameworks via the designated growthof bismuth oxohalide nanoplates on TiO2nanoribbons, and propose them assunlight-driven bifunctional photocatalysts for all-weather removal of pollutants. Thestructural variability of bismuth oxohalide allows the optical absorption of the hybridframework to be monotonically tuneable across the visible spectrum. Meanwhile, thehybridization greatly increases the surface roughness of the frameworks and enables theframeworks to harvest more photons to participate in photocatalytic reactions.Furthermore, the hybridization establishes two potential gradients to promote theseparation of photo-induced electron–hole pairs: the internal electrical fieldperpendicular to the wide surfaces of bismuth oxohalide nanoplates and across thesemiconductor–semiconductor heterojunction. Owing to the synergetic effects of thepermeable mesoporous architecture, the intense visible light absorption, and theefficient charge separation, the hybrid frameworks are capable of all-weather removal ofpollutants: they utilize the inter-ribbon pores to gather pollutants in the dark (behavingas collectors) and they rapidly degrade the pollutants in the day (behaving asphotocatalysts). In particular, the BiOBr@TiO2framework exhibits very impressivesunlight driven photocatalytic activity, which is much higher than commerciallyavailable P25TiO2under the same conditions.2. Through the precoating of TiO2on carbon fiber sheet and the subsequent hydrothermal reaction of the coated species with NaOH and tetrabutyl titanate, wesuccessfully demonstrated the engineering growth of TiO2nanofibers on carbon fibersheet. The resulting sheet exhibits excellent flexibility and enables robust, large-area(~300cm2) fabrication, representing a significant advantage over previous brittle, smallarea nanofibrous macroscopic structures. The adsorption and photodecomposition ofRhodamine B in water showed that the resulting sheet is very convenient for thepurification of contaminated water owing to its combined adsorption and cleaningfunction. This work provides new insight into the construction of a large area, flexibleand robust water purification membrane material.