Fabrication And Modification Of FeVO₄and Their Photocatalytic Activities Under Visible Light

Currently, TiO2and ZnO et al. with higher activity and wide bandgapsemiconductor material are more heterogeneous photocatalysis, can only be ultravioletexcitation. Actually the solar radiation energy which reaches the surface of the earth isconcentrated in the wavelength range460~500nm, while the UV component (300-400nm) is less than5%, so how to make full use of the natural light to take photocatalyticreaction is increasingly people’s interest of the development of visible light.FeVO4as a new type of visible-light photocatalytic materials attracted people’sattention due to it’s high catalytic activity and narrow bandgap. Cause of FeVO4’s goodapplication prospect, our team using sol-gel method to prepared FeVO4with corn strawand studied its microstrucyure and morphology growth mechanism. In order to improvethe photocatalytic activity, doped non-metalic N and S, N-La co-doped, characterizationand analysis by XPS、XRD、SEM、BET and UV-Vis etal, the following several parts ofwork have been done：(1) It was found that the samples calcinated at550℃for4h had the flake structurewhich is the copy of the corn stakl micro-structure and had the best photocatalyticactivity. The decolorization rate of methyl orange can reach to be80%or so, increased34%than that of sample that prepared with no corn stalk template. It indicated that thesample’s morphology was the main reason of higher photocatalytic activity.(2) The N doped FeVO4photocatalysts consist of trclinic phase, the doped Nreplaced the existed O formed N-Fe-O and impurity energy level, the doping of Ncould extend the absorption shoulder. The results of photocatalytic degradation tomethyl orange show that: doping with the appropriate N content can improve thephotocatalytic activity of FeVO4. The optimal photocatalytic activity for all theprepared samples could be reached at the doped N of15%(in molar), thedecoloration rate of the MO for the FeVO4rached56%in100min, much higherthan not doped FeVO4(16.7%). (3) The results demonstrate that all the FeVO4or S doped FeVO4photocatalystsconsist of triclinic phase; it revealed that doping S has great influence on morphologybut a little on specific surface area. The doped S replaced lattice oxygen, generate morevacanies and Fe2+, at the same time enhances the light absorption performance of thesample. The photocatalytic activity was evaluated via visible-light by photocatalyticoxidation of methyl orange (MO). The results of photocatalytic degradation to methylorange show that:6%S doping can highly improve the photocatalytic activity and theMO decoloration rate was more than49%.(4) N-La co-doped FeVO4show that: N-La co-doped FeVO4could improvephotocatalytic activity better,15N-0.1La-FeVO4owns the best activity, thedecoloration rate of the MO for the FeVO4rached92.5%in80min. All theco-doped photocatalysts consist of triclinic phase, at the same time, the co-dopedN-La elaboration the grain, enhanced the visible-light absorption, reduce theforbidden band, for the synergy of N-La that make the photocatalytic activity muchhigher.