Preparation And Properties Of Rare Earth Doped Bi₂MoO₆

Environmental and energy issues are the focus of world attention,solar energy is inexhaustible,more and more researchers have pay attention to develop solar energy.The semiconductor photocatalystSemiconductor using solar energy as energy source has received a lot of attention in water decomposition and photocatalytic degradation of organic dyes.At present,The Bi2MoO6 was found to have photocatalytic properties,however,the absorption range of Bi2MoO6 is from ultraviolet light to 500nm visible light,the utilization rate is low,the current use of rare earth doped diboric acid to achieve up-conversion luminescence is a hot method of modification.In this thesis,the upconversion luminescence powders of Ho3+/Yb3+-Bi2MoO6 were synthesized through hydrothermal method and a heat treatment process as research object,using its photocatalytic activity and upconversion luminescence as the research content,the research content is as follows:at the first,the hydrothermal preparation method of rare earth doped bismuth molybdate,and then control the luminescence properties of bismuth molybdate by controlling the temperature of the reaction system,doping concentration and co doping ratio to study the effects of different reaction conditions on the upconversion minescence and photocatalytic properties.(1)The upconversionl1minescence powders of HoU+-YJAZ-BiVMoJ6 were synthesized through hydrothermal method and roasting treatment process by changing codoping ratio of Ho3+ and Yb3+.The samples were characterized by XRD,SEM and UC-PL.It revealed that the grain size of the sample decreases with the increase of the concentration of Ho3+ and Yb3+,and the sample of Ho3+/Yb3+-Bi2MoO6 emits red and green light at 980nm LD,which corresponds to the Ho3+from 5F4,5S:2 levels to the levels 5I8 and 5F5 levels to the levels 5I8 in Ho'??Yb3+ co-doped system,the luminescence intensity is affected by Ho3+/Yb3+ co-doped amount.(2)By changing the calcination temperature,the upconversion luminescence powders of Ho3+/Yb3+-Bi2MoO6 were prepared by hydrothermal method and roasting treatment process.The effect of the calcination temperature on upconversion luminescence intensity of Ho3+/Yb3+-Bi2Mo06 was discussed.The synthetic samples were characterized by XRD,SEM and DTA.The indicate show that the addition of Ho3+ and Yb3+ makes the particles appear slightly agglomerated.With the increase of temperature,the crystal crystallinity is further improved,the multi-phonon relaxation probability is reduced,and the surface is affected by external influence,result that the luminous intensity is improved.Upconversion luminescence analysis showed that the sample exhibited the strongest luminescence intensity at 450?.(3)The new type of kvisible-light-driven of Ho3+/Yb3+-Bi2MoO6 photocatalyst was prepared by hydrothermal method and roasting treatment process.The Ho3+/Yb3+-Bi2MoO6 was characterized by XRD,SEM,PL,XPS,and the photocatalytic properties of the above Ho3+/Yb3+-Bi2MoO6 were discussed in detail.The results show that Ho3+/Yb3+-Bi2MoO6 exhibited the excellent degradation efficiency(90%)for rhodamine B(RhB)in 50 minutesunder the visible light irradiation.Compared with the undoped Bi2MoO6,its photocatalytic efficiency is obviously improved.