The Construct And Photocatalytic Properties Of Bismuth Based-graphene Oxide Composite Photocatalysts

Recently, people’s eyes focused on bismuth-based oxide photocatalysts with visible light active. Since many Bi3+‐containing compounds have been found to possess a narrow band gap and exhibit high visible light photocatalytic activity because of the hybridized O2 p and Bi 6s2 valence bands. Graphene is a new carbon material which is tightly packed into a single two-dimensional honeycomb lattice structure. Its specific surface area can theoretically reach 2600 m2/g, having excellent thermal conductivity and electrical conductivity. Graphene oxide is derivatives of graphene,that is similar with properties of graphene. In this paper, we use hydrothermal methods will bismuth oxide and graphene oxide composite to prepared a new type of bismuth oxide-graphene oxide composites, and applied to styrene epoxidation catalytic reaction. The major work and achievement in this dissertation were as follows:1. Synthesis, characterization, and applications of mesoporous BiVO₄-GO compound. First of all, we use improved Hummers method to prepared graphene oxide,then mesoporous BiVO₄ was prepared by a dipping process, finally mesopoous BiVO₄-GO composite was prepared by hydrothermal method. The synthesized materials were characterized by X-ray diffraction, FT-IR, UV-vis, transmission electron microscope（TEM） and scanning electron microscope（SEM） etc.The results showed that, GO is encapsulated in the mesoporous BiVO₄. In the oxidation of styrene with H₂O₂ as the oxidant over mesoporous BiVO₄-GO catalyst under photo-irradiation,many reaction parameters were conditioned at length, such the amount of catalyst,reaction time and adding the amount of graphene oxide so on. The results showed that9% mesoporous BiVO₄-GO composite catalyst was more active than other catalysts,The conversion rate of the epoxidation of styrene system can reach 81.50%, the selectivity of epoxy ethyl benzene is 47.89%.2. Synthesis, characterization, and applications of Bi₂MoO₆/BiVO₄/GO compound. We use graphene oxide as a carrier, Bi（NO₃）·5H₂O,（NH₄）₆Mo₇O₂₄·4H₂O andNH₄VO₃ as raw material to synthesis Bi₂MoO₆/BiVO₄/GO compound through the hydrothermal method. The synthesized materials were characterized by X-ray diffraction, FT-IR, UV-vis and scanning electron microscope（SEM） etc. The results showed that, Bi₂MoO₆ and BiVO₄ crystalline particles are not rules, most BiVO₄ is square,most Bi₂MoO₆ is spherical, a small number of particles are gathered together to form larger particles, Bi₂MoO₆ and BiVO₄ particles are distributed on the surface of graphene oxide. The catalytic activity of the catalyst was tested by epoxidation of styrene reaction. The results showed that Bi₂MoO₆/BiVO₄/GO composite catalyst was good active.