Study On The Preparation Of Graphene-based Semiconductor Nanaocomposites And Their Photocatalytic Performances

As known,graphene possesses unique features as a new two-dimension carbon nanomaterial,especially the excellent electron transport ability.So,it has attracted great attentions considering graphene as a promising co-catalyst to improve the catalytic performance of semiconductors in photocatalytic field.However,graphene itself with some inherent side effects,such as the light shielding effect,also reduces the light intensity which semiconductors should obtain,resulting in the restriction of graphene's further employment.At present,researches towards making use of graphene-based semiconductors mainly concentrate upon two aspects:on the one hand,graphene is incorporated into different and novel semiconductors in order to extend the range that graphene can be applied.On the other hand,researchers try their best to minimize graphene's disadvantages for more efficiently utilizing graphene by reasonable framing the construction between graphene and photocatalysts.The following is the main content of the dissertation:(1)Traditionally,graphene is commonly wrapped outside of the semiconductors.Thus,graphene located in the middle of semiconductors and light from the point of relative position,leading to a situation which the light shielding caused by graphene is unavoidable.So,we build an original structure to suppress the shortcoming.Firstly,small graphene oxide sheets are pasted on the surface of SiO2 spheres,which then used as templates to load TiO2 shell precursor.After thermal treatment,TiO2 spherical shell with hidden graphene sheets is obtained.Being well hidden under TiO2 spherical shell,the light shielding influence caused by these graphene sheets is greatly reduced.At the same time,graphene still could play a great role of conducting electrons in the system.Hence,Ti02 spherical shell with graphene exists in its inwall would receive more illumination in comparison to the usual wrapped one.As results,these hidden graphene sheets can better enhance the performance of Ti02 on photocatalytic reduction of nitro-aromatics,even under the condition of excess dosage of them.(2)NaTaO3 with polymolecularity and small size have been prepared successfully by modified hydrothermal synthesis method.Next,going through the attachment of graphene and in-situ photocatalysis reduction,graphene involved NaTaO3 will be obtained.It is found that the photocatalytic performance of NaTaO3 can be enhanced with effect by introduce graphene into the composite.Moreover,it will enlarge the bound of graphene's application in the photocatalysis areas.