Study On Peparation And Photocatalytic Activity Of Binary Composite Titanate

In this study,K₂Ti₆O₁₃ materials were synthesized by sol-gel route,and t and Yb-K₂Ti₆O₁₃ and Yb-K₂Ti₆O₁₃（PEGn）photocatalysts were prepared by two modifications:doping with Yb³⁺and addition of polyethylene glycol（PEG）.On the effectiveness of K₂Ti₆O₁₃ photocatalytic degradation of Acid Red 1 solution,the impacts of Yb³⁺doping amount,polyethylene glycol molecular weight and dosage were examined.There are various characterization methods to analyze the photocatalytic activity of the above titanate materials,such as XRD,SEM,EDS,BET and BJH and PL spectroscopy.The main studies were as follows.（1）The Yb-K₂Ti₆O₁₃ photocatalyst was synthesized by doping Yb³⁺to K₂Ti₆O₁₃which was the main titanate.Under UV light,Acid Red 1 solution was photocatalytically degraded by Yb-K₂Ti₆O₁₃,and the doping percentage of Yb³⁺at the greatest dye degradation efficiency was found to be 15%.The intensity of the diffraction peaks of Yb-K₂Ti₆O₁₃ increased to different degrees compared to pure K₂Ti₆O₁₃,and the addition of Yb³⁺promoted the growth of crystals on the crystalline planes of（310）,（-203）and（020）.The 15%Yb-K₂Ti₆O₁₃ has the largest grain size and specific surface area of this series of samples.The 15%Yb-K₂Ti₆O₁₃ also has the lowest electron-hole pair complexation efficiency of the series and produces more hydroxyl radicals compared to K₂Ti₆O₁₃ and 30%Yb-K₂Ti₆O₁₃.Under UV illumination,the total removal rate of K₂Ti₆O₁₃ from Acid Red 1 solution was only 23.6%,while the total removal rate of 15%Yb-K₂Ti₆O₁₃ under the same conditions was up to 49.3%.（2）Polyethylene glycol was used as template agent in a sol-gel route to synthesize porous 15%Yb-K₂Ti₆O₁₃（PEGn）photocatalyst.The X-ray diffraction spectra confirmed that the addition of PEG promoted the growth of Y Yb-K₂Ti₆O₁₃ grains to different degrees.The 15%Yb-K₂Ti₆O₁₃（PEG2000）has the strongest the largest grain size and the largest specific surface area.Scanning electron microscopy images of the samples showed that the addition of PEG made the surface of the 15%Yb-K₂Ti₆O₁₃ material sparse and porous.Under UV illumination,the total removal rate of 15%Yb-K₂Ti₆O₁₃was 49.3%for the Acid Red 1 solution,while the total removal rate of15%Yb-K₂Ti₆O₁₃（PEG2000）could be increased to 88.3%under the same conditions.The 15%Yb-K₂Ti₆O₁₃（PEG2000）has great photocatalytic stability,and the photocatalytic activity was 64.1%after 5 cycles of use as verified by cycling experiments.（3）The effect of varying the amount of PEG2000 on the efficiency of15%Yb-K₂Ti₆O₁₃ photocatalytic degradation of Acid Red 1 solution was investigated.X-ray diffraction spectra showed that the addition of 1.5 g PEG2000 was most favorable for the growth of crystals on each crystal plane of 15%Yb-K₂Ti₆O₁₃.Also,15%Yb-K₂Ti₆O₁₃（1.5 PEG2000）has the largest specific surface area in this series of samples.Fluorescence spectra also confirmed that 1.5 g of PEG2000 could make15%Yb-K₂Ti₆O₁₃ produce the highest number of hydroxyl radicals and have the lowest electron-hole pair complexation efficiency.The 15%Yb-K₂Ti₆O₁₃（1.5PEG2000）largely removed the main contaminants from the Acid Red 1 at 50 min of UV illumination,at which time the total removal rate of the dye by the 15%15%Yb-K₂Ti₆O₁₃ photocatalyst was only 76.6%.