Photocatalytic Activity Of Bismuth Titanium Oxide(Bi₄Ti₃O₁₂) Nanosheets Promoted With Silver Nanoparticles

Photocatalysis is a recognized approach where light energy is employed to excite the semiconductor material producing electron/hole pair which eventually involves in the detoxification of pollutants(in water or air)and in water splitting.Photocatalytic processes have attracted considerable attention in the field of waste-water treatment.However,existing photocatalysts suffer from poor activity or no activity in the visible light region which restricts them from solar light utilization.This work mainly focuses on applications of photocatalysis in degradation of organic pollutants.Bismuth was loaded on TiO2 photocatalyst by a sol-gel hydrothermal process to synthesize bismuth titanium oxide(Bi4Ti3O12,BTO).The photocatalytic activity of BTO was improved by loading silver nanoparticles(AgNPs)by photo-assisted reduction.The optimum weight percent of loading AgNPs was found to be 1.5%.The photocatalytic degradation efficiency of Bi4Ti3O12/Ag nanosheets reached as high as 99.0%of rhodamine B(RhB,100 ml,6 ppm of initial concentration)under 70 min of visible light(>420nm)irradiation.The effect of pH on the photocatalytic activity of Bi4Ti3O12/Ag was also studied and found that reduction of pH in the range of 3-11 resulted in faster degradation of RhB.Modifying Bi4Ti3O12 with Ag significantly increases the adsorption capacity,the photoelectric conversion performance,and the electrical conductivity.The influence of sodium hydroxide concentration used for the synthesis of BTO nanosheets was examined and it was found that 5.0 M(75 ml)is the optimum concentration for the synthesis of porous,regular,thin,almost equal size nanosheets.In addition,the effect of titania source was studied and it was found that titanium butoxide[Ti(n-BuO)4]is much better than titanium isopropoxide[Ti(i-PrO)4]in producing regular nanosheets.