Preparation And Photocatalytic Properties Of Novel Carbon Nitride Materials

Semiconductor photocatalysis technology has considered as the most promising method in resolving the problem of energy shortage and environmental pollution, the core technology is the photocatalyst research. Carbon nitride is a new type of non-metallic semiconductor photocatalyst with good thermal stability and chemical stability, high photogenerated electron and hole separation efficiency and strong role to the absorption of visible light. However, the common photocatalysts such as titanium dioxide on the utilization of visible light is relatively low, there are great limitations in practical applications. Mesoporous carbon nitride materials have high thermal stability, chemical stability, high utilization of visible light, cheap raw materials and easy preparation, simple preparation process, and have very broad application prospects in catalytic purification environment and energy cleaning. In this paper, the preparation conditions of new carbon nitride materials were studied, and the effects of different carbon nitride materials on the photocatalytic performance were investigated.In this paper, three kinds of carbon nitride materials with different morphologies were prepared by hard template method with different sizes of silica as hard template, and their photocatalytic degradation of MB and RhB were investigated. The effects of carbon nitride with different morphologies on photocatalytic activity were also investigated. The main research work of this paper is as follows:Firstly, mesoporous silica was used as a template to synthesize the mesoporous carbon nanocomposites with the encapsulation mechanism as the main mechanism. The size and morphology of the microspheres were characterized. The photocatalytic degradation of MB and the effect of different concentration of carbon nitride on the photocatalytic activity were studied. The photocatalytic degradation of MB was also observed under visible light.The photocatalytic activity of mesoporous carbon nanotubes with 85% cyanamide - ethanol mass ratio was the highest.Secondly, through the submicron silica as hard template, the three-dimensional macroporous carbon nitride material was synthesized and characterized, and the size of the template was changed and the photocatalytic degradation was evaluated. RhB test showed that the photocatalytic activity of the three-dimensional macroporous carbonitride was 10000r at the centrifugal speed of 10000r, and the photocatalytic activity of RhB solution was the best.Thirdly, the mesoporous carbon nanotubes were prepared by using nano-scale silica gel solution as hard template. The specific surface area of carbon nitride was controlled by adjusting the ratio of silica gel and cyanamide, and the photocatalytic degradation experiment was also carried out. RhB, the ratio of cyanamide to silica gel was 1: 1.6, the photocatalytic activity of irregular mesoporous carbon nitride was the best.