Preparation And Photocatalytic Properties Of Bismuth Vanadate

With global energy crisis and environmental pollution problem gettingserious,semiconductor-mediated heterogeneous photocatalysis using sunlight as energyis a very good outlooking technology for depuration without generating harmfulby-products,the photocatalyst is the significant key for the photocatalysis.TheBi-systerm ternary oxide BiVO4degrade pollutants very effective,and itsstability,non-toxic,low energy gap so that has became the focus in light-catalysis.Through the hydrothermal method,we prepared polyhedral,blocky shapes ofmonoclinic BiVO4materials based on Bi(NO3)3·5H2O and NH4VO3. The BiVO4sampleswere represent by XRD,SEM et.al, to study the effect of pH value,temperature, dwelltime and the use level of surface-active agent on crystal structure,morphology andcatalytic performance of samples,The BiVO4materials were used to degrade RhB,toexamines BiVO4samples photoctalytic ability.The results show that good monoclinicBiVO4can be obtained via a hydrothermal route of110℃,24h, with the recipe ofBi:V:CTAB=1:1:1in molar ratio, the solution for neutral,which possess highestphotocatalytic activity under the visible light irradiation.More than90%of RhB weredegraded after visible light irradiation for three hours.The BiVO4samples were blockstructure.To solve the problems that BiVO4has higher recombination rate of electronic-hole,and lower utilization rate of light quanta,By introducing the rare earth metal ions oncatalyst modification,wo try to improve its photocatalytic activity under the visible lightirradiation.Experimental investigation shows that the hydrothermal synthesis leads to amixed phase system as yttrium is incorporated,in the case of the monoclinic phase Y3+probably occupies the interstitial positions, while for the tetragonal structure the substitutional position is more evident.The result shows that photocatalytic activity wasimproved and samples exhibit the better photocatalytic activity than the other sampleswhen the adding volume of Y is3at.%under the same conditions. It is considered thatboth semiconductor composite and ion doping can make plenty of the lattice distortionso that improve the utilization efficiency of light quanta by lower recombination rate ofelectronic-hole and then, the catalytic performance is significantly improved.