Preparation Of Bi₂WO₆@TiO₂Nanowires Composite Photocatalyst And Study On Its Photocatalytic Performance

With the development of photocatalytic degradation of pollutantstechnology, researchers pay more attention to the study on TiO2photocatalyst inthe past decades. However, restricted by low photo-quantum efficiency andnarrow responding range to the solar light, the photocatalytic activity of thenaked TiO2is comparatively low. Based on the decrease the recombination ofphotoelectron and hole greatly and broaden the range of spectral response, in thispaper we prepared1D TiO2nanowires coupling narrow-band-gap semiconductorBi2WO6, which present the improved absorption in the visible region. And theBi2WO6@TiO2nanowires composite photocatalysts with the effectiveheterojunction structure improve the separation efficiency of photoinducedcharge.In the paper, the TiO2nanowires(TNWS) is prepared used butyl titanate astitanium resource by concentrated alkaline hydrothermal method. TheBi2WO6@TiO2nanowires composite photocatalysts(BWO-TNWS) were preparedby hydrothermal method. The BWO-TNWS composite photocatalysts areprepared by XRD, UV-Vis, SEM, TEM, PL and EIS. Moreover, photocatalyticactivity of the BWO-TNWS for degrading rhodamine B(RhB) and phenolsolution under UV-vis light irradiation are investigated. Meanwhile, the influenceof preparation conditions and photocatalytic degradation system onphotocatalytic activity are also investigated.The characterization results show that the prepared TNWS presents anataseform, the diameter of TNWS is about80nm. BWO is orthorhombic phase and theparticle size is about30~40nm. The TEM images confirm that BWOnano-particles cover the1D TiO2nanostructure closely. The BWO-TNWS composite photocatalysts present the improved absorption in the visible regiondue to coupling narrow-band-gap semiconductor Bi2WO6. PL analysis resultshows BWO-TNWS composite have a lower peak than that of TNWS, whichindicates that the composite improve the separation efficiency of thephoto-induced electron-hole pairs. In addition, in the EIS the observed arc radiiof TNWS are decreased after coupling with an appropriate amount of BWO. Itindicates that effective heterojunction structure was formed between TNWS andBWO which promotes the separation of photo generated electron-hole pairs andaccelerates interfacial reaction rate.In order to explore the influence of preparation conditions on theBWO-TNWS catalytic activity, the degrading activities of RhB and phenolsolution were investigated.20%BWO-TNWS composite catalysts show excellentphotocatalytic activity when the temperature of hydrothermal reaction is180℃with butyl titanate as titanium resource, ethylene glycol as solvent. The reactionsystem for degrading the RhB and phenol solution is also optimized. It can beconcluded that the best adding amount of BWO-TNWS composite catalyst is1.0g·L-1, initial concentration of the liquid is20mg/L. The20%BWO-TNWScomposite exhibits the highest degradation rate of RhB (phenol) up to78%(33%).