Synthesis And Photocatalytic Properties Of G-C₃N₄-Based Composite Materials

Semiconductor photocatalytic technology,which has developed for 30 years,is an emerging technology of green,environmental protection,high efficiency,energy saving.In resent years,photocatalytic technology shows a wide application prospect in the field of environment pollution,which has been widely attention and become one of research hot spots.At present,the development of photocatalyst is mainly concentrated in the traditional photocatalyst such as TiO2?ZnO.They can use only ultraviolet light,solor energy conversion efficiency is low,light electrons and holes are easy to compound,which greatly limit its use in actual production and life.So it is an urgent need to develop higher photocatalytic properties under visible light.Graphite carbon nitride(g-C3N4),which has good chemical stability,thermal stability,resistance to acid and alkali and certain absorption in visible light,has become a research focus of scientists in recent years.However,a single g-C3N4 photocatalyst has high recombination of photoelectrons and holes pair and narrow response range to visible light.So g-C3N4 need to be modified in order to improve the photocatalytic activity.g-C3N4 which has a two-dimensional plane structure can be used as base material and construct the g-C3N4-based heterojunction composite photocatalyst.The paper construct the g-C3N4-base heterjunction composition by ultrasonic assisted precipitation which the photocatalytic activity approve significantly.The research content of the paper are:(1)g-C3N4 nanosheets are prepared by exfoliation bulk g-C3N4 of liquid phase ultrasonic,which H2O and IPA were used as solvents.By characterization,we can see that bulk g-C3N4 were successfully exfoliated into nanosheets,which are thinner,specific surface are larger.The experimental results show that the photocatalytic activity of g-C3N4 nanosheets is higher than that of bulk g-C3N4.(2)Bi2O3/g-C3N4 heterojunction photocatalyst is prepared by a facile corprecipitation method and has been carried on the detailed characterization.The experimental results show that the photocatalytic activity of Bi2O3/g-C3N4 is higher than that of pure Bi2O3 ang g-C3N4.When the mass fraction of Bi2O3 is 10%,the degradation rate of 10mg/L RhB can reach 68%after 3 hours with visible light irradiation.(3)Ag3PO4@g-C3N4 core-shell structure is prepared by ultrasonic assisted precipitation.According to the SEM and TEM characterization methods,we can see that Ag3PO4 particle is wrapped with g-C3N4 nanosheets and constitute heterojunction structure which has the great stability and photocatalytic activity.The results show that Ag3PO4@g-C3N410wt.%has the best photocatalytic activity which can fully degradate 10mg/L RhB in 15 minutes and still be high photocatalytic activities after cycle four times.