Fabrication Of TiO₂-based Floating Photocatalyst And Its Photocatalytic Performance

Photocatalysis is an advanced oxidation process that transforms solar energy into chemical energy.Due to powerful oxidation capacity and no dangerous chemicals consumption,photocatalysis is regarded as a potential technique.However,TiO₂,as a typical photocatalyst,which faces great challenging in its application,such as difficult recycling,low light utilization and photoinduced carrier separation efficiency.In this paper,the above shortcomings of TiO₂ are solved through the optimization of fabrication method,photocatalyst and carrier.The main contents and conclusions of this paper are as follows:1.Herein,ethylene-vinyl acetate copolymer（EVA）was investigated as a support to prepare floating TiO₂/EVA using a simple thermal crosslinking procedure.Multiple characterization analyses demonstrated that TiO₂ was anchored onto EVA surface evenly via hydrogen-bond-enhanced physical crosslinking,and remained its virgin crystal structure.The photocatalytic performance of TiO₂/EVA was investigated using Rh B as model pollutant.Due to the significantly improved adsorption and photocatalytic performance,the removal efficiency of Rh B by floating TiO₂/EVA was increased by 33.8%compared to suspended pure TiO₂.The degradation mechanism of pollutants in TiO₂/EVA system was revealed with the combination of product analysis and free radical quenching experiment,the results showed that h⁺and·O₂^-played dominant roles in TiO₂/EVA-driven Rh B degradation.A 30-day stability test demonstrated that TiO₂/EVA had a high thermal,p H,and photo-stability.Three-run reuse test proved that TiO₂/EVA exhibited satisfactory reusability.This study provides a new stratigy for the preparation of floating photocatalyst.2.Visible light photocatalyst g-C₃N₄ was investigated to optimize the photocatalytic performance of TiO₂/EVA.Given that TiO₂ shows photocatalytic activity only under ultraviolet light irradiation,g-C₃N₄was selected to develop new TiO₂ photocatalyst by enhancing light havesting.Multiple analyses were used to characterize the morphology and structure of g-C₃N₄-TiO₂/EVA.The results showed that g-C₃N₄ and TiO₂ were successfully coupled,and dispersed firmly on EVA surface through physical cross-linking with retained crystal structure.Ultraviolet-visible spectroscopy（UV-vis）was used to analyze the absorbance properties,and the results showed the coupling of g-C₃N₄significantly improved the light absorption performance of TiO₂.The photocatalytic performance of g-C₃N₄-TiO₂/EVA was evaluated by Rh B.Compared with TiO₂/EVA,the removal effficiency of Rh B increased by 45.9%,14.4%and 17.8%under visible,ultraviolet and simulated sunlight irradiation,respectively,indicating improved photocatalytic performance of TiO₂/EVA with g-C₃N₄ coupling.The quenching experiment showed that h⁺and·O₂^-were the active species in the photocatalytic degradation of Rh B,and·O₂^-was the dominant.Finally,three-cycle tests proved that g-C₃N₄-TiO₂/EVA exhibited satisfactory reusability.This study provides an effective method for TiO₂ absorbance property optimizing,and improves the utilization efficiency of light energy.3.The photoinduced carrier separation property of TiO₂ was optimized by using cellulose carbon aerogel as floating carrier.After solvothermal process,floating photocatalyst TiO₂/CCA was obtained by depositing TiO₂ on CCA carrier.Multiple characterization results showed that TiO₂/CCA possessed a three-dimensional porous structure,in which TiO₂ was fixed on the CCA carrier by forming new chemical bonds（Ti-O-C）.The photoinduced carrier separation efficiency of TiO₂/CCA was characterized by EIS and PL spectrum,and satisfactory results were acquired after TiO₂ loading.The performance of TiO₂/CCA was evaluated by adsorption and photocatalytic experiments.Compared with powder TiO₂,TiO₂/CCA showed good adsorption performance,and with improved Rh B degradation efficiency（41.4%）under simulated sunlight irradiation.The quenching experiment showed that h⁺and·O₂^-were the main active species in the photocatalytic degradation of Rh B.Finally,the reusability of TiO₂/CCA was evaluated by a triple-cycle test.This work fabricates a floating photocatalyst with enhaced photocarriers separation efficiency and provides a new selection for photocatalytic performance improvement.