Preparation Of Graphite Phase Carbon Nitride-based Nanocomposites Materials And Studies On The Application Of Waste Gas Treatment

Air pollution is one of the most serious environmental problems,and nitrogen oxides are one of the most important pollutants.In order to reduce the pollution of nitrogen oxides,a variety of methods have been developed,such as catalytic method,adsorption method,catalytic decomposition method,liquid absorption method,microbial method and photocatalytic method.Due to mild reaction conditions,low energy consumption,less secondary pollution and other advantages,the photocatalytic method become a great potential for development.The key to photocatalysis is to find efficient and stable photocatalysts.Graphite phase carbon nitride is a new type of photocatalyst with the advantages of simple synthesis,suitable electronic band structure,high physical and chemical stability and rich content,etc.Thus it has been more and more favored in dealing with environmental pollution.In this paper,a series of nanocomposites based on graphite carbonitride were prepared for the problem of increasing nitrogen oxides pollution.(1)The hollow mesoporous carbon nitride nanosphere HCNS was prepared by hard template method.HCNS / rGO was obtained by linking reduced graphene oxide on its surface.Finally,for practical application,HCNS / rGO was immobiled on carbon fiber by electrospinning.Then carbon fiber membranes with photocatalytic properties was obtained.The experimental results show that HCNS / rGO has good photocatalytic activity with 64% removal efficiency of low concentration NO in air under visible light irradiation.CNCF has 60% removal efficiency under the same conditions,and has good catalytic recycle performance.In addition,the photocatalytic performance of HCNS / rGO and CNCF is better than that of bulk carbon nitride and HCNS,which indicates that the morphological regulation and the introduction of rGO promote the photocatalytic performance of carbon nitride.(2)The porous beehive-like carbon nitride BCN was prepared by template method.Then BCN was mixed with reduced graphene oxide to obtain nanocomposite BCN / RGO.The material increases the specific surface area by controlling the porosity of the carbon nitride,and the introduction of the reduced graphene oxide promotes the transmission of photogenerated electrons,thereby inhibiting the recombination of the photo-generated electron-hole pairs.The experimental results show that the removal efficiency of BCN / RGO in air is 46%,which is better than 31% of BCN and 25% of bulk carbon nitride.What's more,BCN/RGO has excellent catalytic recycle performance.(3)The CNNS was prepared by ultrasonic exfoliation method.The hollow spherical molybdenum disulfide(HNS)was prepared by solvothermal method.The HNS / CNNS was synthesized and the HNS content was adjusted to prepare different fraction of HNS /CNNS.2D nanosheet carbonitride indicates that there are more active sites,and the introduction of HNS can inhibit the recombination of photogenerated electron-hole pairs in nanocomposites.The results showed that the removal efficiency of NO in different concentrations of HNS / CNNS was higher than that of CNNS;removal efficiency of 5% HNS/ CNNS was of the highest,reaching 53%.And photocatalytic performance of CNNS is also higher than bulk carbon nitride.