It Is Used For The Research Of Graphite Phase Carbon Nitride Macrophotocatalyst In The Field Of Air Purification

Graphite nitride,an inorganic non-metallic semiconductor material,has excellent thermal stability,chemical stability and suitable energy band,which has a great application prospect in the field of photocatalysis.In this paper,we mainly focus on the preparation,modification of graphite-nitride carbon as well as the preparation of g-C3N4-based monolithic photocatalyst for degrading NO.Firstly,the photocatalytic activity of g-C3N4 produced by different precursor in muff furnace was compared,and the optimal g-C3N4 was screened out.Next,the g-C3N4 was modified by concentrated sulfuric acid and potassium ferrate and the influence of modified time on photocatalytic activity was also studied.The experimental results show that O-g-C3N4-K-3h achieves the maximum removal efficiency of NO in visible light,which is 45.82%,which is mainly attributed to the enhancement of light absorption.Subsequently,we studied the influence of concentrated sulfuric acid on the photocatalytic activity of protonated g-C3N4,the results show that the activity of O-g-C3N4-3h is close to O-g-C3N4-K-3h,the increased photocatalytic activity is derived from the increased specific surface area and the enhanced separation ability of photogenerated electrons and holes.Finally,because of the high cost of potassium ferrate,it is considered that O-g-C3N4-3h is a better modified product.Then,on the basis of the above studies,in order to expand the practical application of protonated g-C3N4,graphene oxide is selected as a carrier,the sample of O-g-C3N4-3h was loaded onto graphene oxide to form a monolithic photocatalyst by facile one-step freeze-drying method.The obtained O-g-C3N4/GO aerogel shows a large surface area,enhanced visible-light absorption capacity,and rapid separation of photogenerated electrons and holes,which make it an enhanced photocatalytic activity.But the preparation of O-g-C3N4/GO aerogel has many disadvantages,such as sophisticated procedures,high cost and poor mechanical strength.Finally,in order to further improve the photocatalytic activity and mechanical strength of g-C3N4 monolithic photocatalyst,we chose the melamine sponge(MS)as the carrier and have successfully prepared g-C3N4/MS monolith photocatalyst.The studies show that the monolithic photocatalyst has an enhanced photocatalytic activity in photodegradation NO,rhodamine B and photoreduction CO2,which is due to the enhanced specific surface area,the absorption capacity of visible light and fast separation ability of photon-generated carrier.Moreover,the prepared g-C3N4/MS monolithic photocatalyst has ultra-low density,high porosity and excellent mechanical strength and firm connection between g-C3N4 and melamine sponge,which make g-C3N4/MS monolithic photocatalyst better adapted to practical applications.In addition,the simple preparation process and low cost of raw materials enable it to achieve large-scale production and application.