Preparation Of Layered Double Hydroxides-Based Materials With Photocatalytic Performance

In this thesis, Cu-Cr layered double hydroxide （CuCr-LDH） filmsand ZnGa-mixed metal oxides （ZnGa-MMOs） derived from ZnGa-LDHsprecursor have been fabricated, which were used as visible-lightresponsive photocatalyst for the degradation of organic pollutants andsplitting water into hydrogen respectively.Oriented CuCr-LDH films were fabricated by the electrophoreticdeposition method （EPD） on copper substrates, which can be used asphotocatalysts for the degradation of organic pollutants under visible-light irradiation. Powder X-ray diffraction （PXRD）, scanning electronmicroscope （SEM）, Fourier transform infrared （FT-IR） and Brunauer-Emmett-Teller （BET） reveal that the resulting CuCr-LDH film possesseshigh crystallinity, porous structure as well as large specific surface area.UV-vis diffuse reflection spectroscopy （DRS） confirms that the CuCr-LDH film shows a broad absorption in visible-light region （>400nm）.The LDH film thickness can be controlled precisely by adjusting voltageor time of EPD. The film with thickness of16.5μm shows excellentphotocatalytic activity for the degradation of2,4,6-trichlorophenol （2,4,6- TCP）, sulforhodamine B （SRB） and Congo red. The photocatalyticreaction kinetics of2,4,6-TCP was appropriately described by thepseudo-first-order model. In addition, the LDH film exhibits excellentrecycleability compared with the corresponding powder sample, whichfacilitates its repeatable and cyclic usage over a long period. Owing to thehigh efficiency, low-cost preparation, easy manipulation and recyclability,it is expected that this film can be potentially used as photocatalyst in thefield of water treatment.ZnGa-MMO material was prepared by calcination of pure ZnGa-LDH precursor at500℃, which was employed as photocatalyst for watersplitting into hydrogen. PXRD, SEM, High Resolution TransmissionElectron Microscopy （HRTEM） and X-ray photoelectron spectroscopy（XPS） show that ZnGa-MMO with Zn O Ga interaction almost keepsthe morphology of ZnGa-LDH. Moreover, the band gap was estimated tobe2.85eV by DRS. The influences of Zn/Ga molar ratio, calcinationtemperature, sacrificial agent and loading amount of Pt were studiedthroughly. The sample of ZnGa-MMO derived at500℃loaded with0.5wt%Pt exhibits excellent photocatalytic performance in S^2- and SO₃^2- solution （H₂production rate:31.2μmol/h;0.5g catalyst in UV-vis light）.