Preparation Of TiO₂-rGO Loading Au And Pd And Its Photocatalytic Performance

At present,the water pollution is becoming more and more serious.In this field,the study and application of the advanced oxidation technologies which is represented by the photocatalysis technology is used more widely.In addition,the most commonly used semiconductor is TiO₂ photocatalyst.In this thesis,we modified TiO₂ and studied the photocatalytic performance of the modified photocatalysts under the UV irradiation.In the experiment,we applied the hydrothermal method and the combined calcination method to prepare TiO₂-rGO composite photocatalyst.On this basis,we also prepared TiO₂-rGO-Au-Pd photocatalysts using the light reduction deposition method and characterized them with X-ray diffraction（XRD）,ultraviolet-visible diffuse reflectance spectroscopy（DRS）,scanning electron microscope（SEM）and X-ray photoelectron spectroscopy（XPS）.This thesis studied the optimal composition of the photocatalyst including the best amount of rGO and the best load of Au and Pd which was 3 % and 0.45 % proved by the experiment.In the experiment,we used the organic dyes RhB and 2,4-DCP as simulated pollutants to further study the photocatalytic performance and influential factors of the photocatalyst.The results illustrated that the optimalamount of photocatalyst was 1.00 mg/mL in which the photocatalytic degradation of TiO₂-rGO-Au-Pd was the strongest,the degradation efficiency of RhB was 94.30 % and the degradation efficiency of 2,4-DCP was 86.62 %（the TOC degradation efficiency was 46.89 %）.In addition,we studied the influence of solution’s initial pHandpollutants’ initial concentration on the photocatalytic effect and researched the stability of the photocatalysts.The results indicated that the optimal initial pH of degradating RhB and 2,4-DCP was 7 and 6.Besides,the photocatalytic performance was decreasing while the initial concentration was increasing.Therefore,the photocatalysts had better stability.In the end,we got the degradation kinetics constants through the fitting of thedegradation kinetics of RhB and 2,4-DCP and discussed the degradation mechanism of the photocatalysts in the degradation of organic pollutants.