Preparation Of Metal Oxide/graphitic Carbon Nitride Composite And Its Photocatalytic Activity

Photocatalytic technology is an effective method to solve the environment and energy problems.The conventional photocatalysts?such as titanium dioxide,zinc oxide,etc.?are only responsive to ultraviolet light and cannot effectively utilize visible light.The graphitic carbon nitride?g-C₃N₄?has attracted much attention because of its response to visible light,simple preparation and high stability.However,g-C₃N₄ suffers from several disadvantages,including low utilization of sunlight,low specific surface area,and so on.It is of great significance to develop a highly efficient and stable g-C₃N₄ photocatalyst with visible light response.In this paper,two kinds of metal oxide modified g-C₃N₄ materials were prepared by a simple and economical grafting method:3,4-dihydroxybenzaldehyde functionalized?-Fe₂O₃ nanoparticles and g-C₃N₄ composite??-Fe₂O₃-DBD/g-C₃N₄?,3,4-dihydroxylbenzaldehyde functionalized Ga₂O₃ nanoparticles and g-C₃N₄composite?Ga₂O₃-DBD/g-C₃N₄?.The materials were characterized by a series of methods and applied to visible light catalytic oxidation degradation of pollutants in the environment.The main results are as follows:Aldehyde-functionalized?-Fe₂O₃/g-C₃N₄ was successfully synthesized through Schiff-based reaction between aromatic aldehydes in 3,4-dihydroxybenzaldehyde and-NH₂ groups in urea.The 3,4-dihydroxybenzaldehyde around?-Fe₂O₃ were advantageous to in situ growth of g-C₃N₄ on?-Fe₂O₃ to form the contact interface by chemical bonds and beneficial to the electron transfer,leading to the formation of Z-scheme photocatalytic system.The?-Fe₂O₃-DBD/g-C₃N₄ photocatalysts exhibited a remarkable improvement in the degradation of bisphenol A compared with bulk g-C₃N₄.The enhanced photocatalytic activity was attributed to the enhanced charge separation efficiency and higher redox potential.The experimental results showed that the composite photocatalyst greatly improves the mineralization rate of bisphenol A.Aldehyde-functionalized Ga₂O₃-DBD/g-C₃N₄ was successfully synthesized by a Schiff-based reaction of synthetic Ga₂O₃-DBD Nanoparticles and urea.In this system,a well-conductive aromatic ring acts as an electron transporter,which promotes the transfer of photogenerated electrons,improves the separation rate of photogenerated electron-hole pairs.The Ga₂O₃-DBD/g-C₃N₄ exhibited a wide visible light absorption range,high charge-separation efficiency and high redox potential,thus improving the photocatalytic performance of the Ga₂O₃-DBD/g-C₃N₄ photocatalyst.