| Photocatalytic technology is an efficient and environmental-friendly access in environmental pollution control.In this paper,graphite carbon nitride（g-C3N4）was used as the research object.In view of the small surface area and the photocatalytic efficiency which because electron-hole pair recombination of g-C3N4.We used morphological control and grapheme doping composite photocatalyst to enriched the surface area and the catalytic efficiency.The catalysts were analyzed by XRD,FT-IR,TEM,BET,TGA and UV-vis.The photocatalytic activity were determined by photocatalytic degradation of methyl orange.The specific research contents and achievements are as follows:The mesoporous graphitic carbon nitride（mpg-C3N4）with larger specific surface area and pore size was prepared by calcined the mixture of silica and dicyandiamide with different time and different temperature.The results of TEM and BET showed that there was mesoporous structure existed in mpg-C3N4,which has a larger specific surface area and pore size distribution compared to g-C3N4.Photocatalysis experiment shows that the ratio of silica to dicyandiamide was 1.2/1 and calcined 4 hour at 550 ℃ has the best photocatalytic activity,which can remove 99% of the methyl orange in 2.5 hours.Graphene oxide（GO）which prepared by modified Hummers method was added to the preparation of mpg-C3N4.The prepared mpg-C3N4/rGO composite photocatalyst which catalytic performance is more excellent.The results show that the graphene is well intercalated in mpg-C3N4,and the addition of GO does not destroy the synthesis of mpg-C3N4 during heating.The results of UV-vis test show that the photocatalytic performance is enhanced and the band gapwidth is reduced which increase the utilization rate of the visible light.Photocatalytic results showed that the catalytic effect of mpg-C3N4/rGO is the best when the molar ratio of GO is 0.5%.In the photocatalytic system,the main active substances are（h+）and（·O2-）,while（·OH）has little effect. |
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