Modification?Loaded And Photocatalytic Performance Study Of Graphite Carbon Nitride?g-C₃N₄?

Graphite carbon nitride?g-C₃N₄?is a kind of graphite structure of carbon compounds.Due to its unique semiconductor band structure and high chemical stability,g-C₃N₄,as a non-metallic semiconductor photocatalyst,was introduced in the field of photocatalysis attracted widespread attention.The g-C₃N₄ was very cheap and stable.It can meet the basic requirement as light catalyst and have the chemical composition of polymer semiconductor.The energy band structure of it was controlled easily.So the g-C₃N₄ was considered to be a worthy researched in the field of photocatalytic material.However,due to the materials properties of polymer,the g-C₃N₄ as photocatalyst also has many problems to be solved,such as lower specific surface area,higher excited binding energy,lower crystallinity,wider forbidden band.The quantum efficiency of it was low in the photocatalytic process.So the utilization ratio of solar energy was low.Furthermore,the catalyst powder was easy to aggregate and bad for recycling.In this paper,the block g-C₃N₄ was prepaered by the melamine via the high temperature pyrolysis.On one hand,the block g-C₃N₄ was stripped by the concentrated sulfuric acid to obtain the flake of g-C₃N₄.The prepared samples were charactered by scanning electron microscopy?SEM?,infrared spectroscopy,XRD methods and so on.The results were showed that the morphology of g-C₃N₄ was sheet structure,and the size was smaller.On the other hand,The protonated g-C₃N₄ was obtained by nitric acid through the hydrothermal method to dealt with the blockg-C₃N₄.The prepared samples were charactered by scanning electron microscopy?SEM?,infrared spectroscopy,XRD methods and so on.The results were showed that the size of the protonated g-C₃N₄ was smaller,and some aromatic heterocycles are destroyed,simultaneously the crystal crystallinity is improved.The porous g-C₃N₄ was obtained through the pyrolysis of melamine as the precursor with the template agent of surfactant OP-10,F127 and AEO-9.The scanning electron microscopy?SEM?analysis showed that the porous g-C₃N₄ structure was loosest with the surfactant OP-10.The photocatalytic degradation of methylene blue test showed that the flake,protoned and porous g-C₃N₄ showed better dispersion in aqueous solution.The photocatalytic activities of them were improved significantly.The Ag/g-C₃N₄ composite photocatalyst was ground by the morphology of g-C₃N₄ and silver nitrate through a simple solid method.The Ag was deposited uniformly on the sheet structure of the g-C₃N₄,and the g-C₃N₄ was gotten further elaboration.Compared to the block g-C₃N₄,the stripped g-C₃N₄ and Ag/g-C₃N₄ have good dispersion in aqueous solution.The photocatalytic degradation of methylene blue test showed that the photocatalytic activity was improved obviously.The Ag/g-C₃N₄ composite catalyst could catalyze the 4-nitrophenol reducted to the4-aminophenol rapidly,and the catalytic activity remained higher after five recycle times.The Cd S/g-C₃N₄ composite photocatalyst was got by the in-situ growth method using g-C₃N₄ prepared by using OP-10 as template.The prepared results of scanning electron microscopy?SEM?,infrared spectroscopy and XRD methods showed that the quantum dots was successfully generated in the structure of g-C₃N₄.When the ratio of Cd S and g-C₃N₄ was 1:1,Cd S can deposited uniformly on the porous structure of g-C₃N₄,and the channels of the g-C₃N₄ still remained fluently.The photocatalytic degradation of methylene blue test showed that CdS/g-C₃N₄ composite photocatalyst possess high catalytic activity not only under ultraviolet light but also under the visible light.When the ratio of the Cd S and g-C₃N₄ was 1:1,the photocatalyst activity of the composite was the best.The g-C₃N₄/carbon fiber,g-C₃N₄/aramid fiber and g-C₃N₄/PAN fiber was obtained by the sol-gel dipping method with the catalyst of the protonated g-C₃N₄ and the carrier of the modified carbon fiber,aramid fiber and PAN fiber.The characterized results revealed that the protonated g-C₃N₄ showed better dispersibility in the aqueous solution and the size was decreased.The protonated g-C₃N₄ can deposited uniformly on the carbon fiber,aramid fiber and PAN fiber.The stablechemical bonds was generated between the functional groups from the modified fiber and g-C₃N₄.The photocatalytic degradation of methylene blue test showed that the three kinds of composites showed a high catalytic activity under the ultraviolet light.The catalytic activity remained higher after 8 recycle times.The strong bonding force between the fibers and g-C₃N₄ solved the problems of recovery and recycling of the the g-C₃N₄ powder catalyst.