The Fabrication And Photoelectrocatalytic Study Of The Composite ZnSe/Au/TiO₂ Nanotubes Films

Anatase titanium dioxide nanotubes(TiO2 NTs)films photoelectrode are successfully fabricated by a solvothermal method,and on this basis we study the impact of Gold nanoparticles(Au NPs)and ZnSe quantum dots(QDs)for photoelectrocatalytic(PEC)activity,the results prove that there is a improvement of PEC performance of of TiO2 NTs deposited with Au NPs and ZnSe QDs on the surface of it,which is approximately 3.5 times higher than that of pure TiO2 NT films.Titanium TiO2 NTs were prepared by a solvothermal process,the morphology of it is controlled by reactive time,temperature and concentration of NaOH.When the reaction temperature is 150 °C,the reaction time is 6 h,the reaction concentration is 5 mol/L or the reaction temperature is 180 °C,the reaction time is 1 h,the reaction concentration is 5 mol/L,the titanium TiO2NTs can been successfully prepared.Au NPs were deposited on the surface of TiO2 NTs by a microwave-assisted chemical reduction route,which formed a composite Au/TiO2 NTs films.The PEC activity of TiO2 NTs doping with noble metal is investigated,which is approximately 1.7 times higher than that of pure TiO2 NT films and the result show that the enhanced photoelectric catalytic activity was owning to the Au NPs localized surface plasmon resonance(LSPR)effect.A aqueous-phase process technique is adopted to construct highly dispersed ZnSe QDs on TiO2 NTs,which formed a composite ZnSe/TiO2 NTs films.The PEC activity of TiO2 NTs doping with narrow gap semiconductor is investigated,which is approximately 1.8 times higher than that of pure TiO2 NT films and the result show that the enhanced photoelectric catalytic activity was owning to the existence of ZnSe QDs.Eventually,anatase TiO2 NTs films photoelectrode are successfully fabricated by a simple and effective hydrothermal method.Subsequently,a aqueous-phase process technique is adopted to construct highly dispersed ZnSe QDs on Au/TiO2NTs films prepared by microwave-assisted chemical reduction route,which formed a composite ZnSe/Au/TiO2 NTs films system with excellent performance in photo-electro-catalytic applications.The PEC activity of ZnSe/Au/TiO2 NTs films is approximately 3.5 times higher than that of pure TiO2 NT films.It is a natural requirement for particle-to-surface contact between Au and TiO2 to construct a potential gradient and then the ZnSe QDs should be located on the Au NPs surface,which indicates that charge separation and migration in the ZATs should comply with the vectorial electron transfer rule of ZnSe → TiO2→ Au→ Ti substrate.The improvement of PEC activity for the degradation of MB due to the synergistic effect of Au NPs,ZnSe QDs and external bias potential and the transmission route of photo-excited electrons,which is divided into two stages:first,they transfer directly from the CB of ZnSe QDs to the CB of TiO2 NTs films and then divert to Au NPs,complying with the vectorial electron transfer rule of ZnSe → TiO2→ Au →Ti substrate.The electron gathered in titanium plate is transmitted to counter electrode,which formed a outer circuit.