Preparation Of Mixed-metal Oxides Photocatalyst And Visible-light-induced Photocatalysis

Industrial wastewater contains a lot of dyes or organic compounds, theseorganisms can not easily be broken down via physical or chemical method andeasily converted to toxic substances, it has caused more and more attention todegrade them through the semiconductor oxide photocatalyst. It is the focus todevelop new nanostructured photocatalytic materials, which could utilizevisible light more effectively. So, based on the above research background, theresearches are present as follows:1. Preparation and photocatalytic research of MgZnIn-MMO photocatalyst.Layered double hydroxides (LDHs) are known as a family of highly orderedtwo-dimensional anionic clay materials. Because different M2+and M3+metalcations with tunable compositions can uniformly distribute and orderlyprearrange at an atomic level within the layers or in the interlayer space in theform of metal complexes. A visible-light-induced heterostructure photocatalystMgO-ZnO-In2O3mixed-metal oxide (MgZnIn-MMO) nanocomposite was synthesized via a co-precipitation method from MgZnIn-hydrotalcite precursorfollowed by calcination. The prepared samples were characterized by X-raydiffraction (XRD), inductively coupled plasma emission spectrometer(ICP-ES), transmission electron microscopy (TEM), Brunauer–Emmett–Teller(BET), diffuse reflectance UV-vis spectra (UV-vis) and Raman spectra(Raman) respectively. We studied the effect on the catalytic performances ofcatalysts with different the ratios of metal ion and calcination temperature.MgZnIn-MMO photocatalyst was used in the degradation of methylene bluedye, and showed excellent photocatalytic performance under the visible light,superior to the commercialization of titanium dioxide (P25). We alsodiscussed the mechanism and kinetics of photocatalyst.2. The research of structure and photocatalytic properties of the compositeZnIn-MMO/Graphene photocatalyst.ZnIn-MMO/Graphene composite with visible light response was fabricatedby a facile one-step solvothermal method. The prepared samples werecharacterized by X-ray diffraction (XRD), transmission electron microscopy(TEM), diffuse reflectance UV-vis spectra (UV-vis) and Raman spectra(Raman) respectively. The degree of photocatalytic activity enhancementdepended on the coverage of graphene on the surface of ZnIn-MMOnanoparticle. The mechanism of the enhanced photocatalytic activity is basedon the synergetic effect between graphene-like carbon and ZnIn-MMO. Thesynergetic effect caused a rapid photoinduced charge separation...