| In recent years,graphitic carbon nitride(g-C3N4)has attracted much attention as a new non-metallic visible light-responsive photocatalyst with high chemical and thermal stability as well as environmental-friendly and cheapness.However,g-C3N4 itself has some shortcomings of smaller surface area and photogenerated carriers to be combined easily,so that its photocatalytic efficiency is less.At present,there have been a variety of modification methods including morphological control,element doping,and recombination with semiconductors to improve the photocatalytic activity of g-C3N4.In this paper,the photocatalytic activity of g-C3N4 was improved by synergistic role of g-C3N4 surface acidification and surface ammoniation.Below are the research contents and results of this paper:1.The graphite type g-C3N4(CN)carbon nitride was obtained by calcining at 550 °C for 4 h by pyrolysis with melamine as raw material.The acidified g-C3N4(CNH)and the ammoniated g-C3N4(CNNH2)were obtained by treatment with hydrochloric acid and ethanolamine,respectively.The results show that the acidified CNH is a thin layer structure,while the ammoniated CNNH2 is still the same as the CN multi-layer structure.Compared with CN’s 460 nm light absorption cutoff wavelength(λcut),Xcut of CNH was extended to 472 nm,and the absorption intensity increased,while λcut of CNNH2 was about 455 nm,and the light absorption intensity was significantly reduced.Under the fixed visible light conditions,the photocatalytic degradation rates of CN,CNH and CNNH2 to RhB were 20%,25%and 8%,respectively,which were correlated with the improvement of light absorption performance.In the evaluation of photocatalytic reduction of C02,the reduction product of CN is mainly ethanol.With the prolongation of illumination time,the amount of production is increasing,and the production rate of is 0.23μmol g-1·h-1.2.a series of AgBr/CNH sample with different mass ratio of m(AgBr)/m(CNH)= 0.3,0.5,0.7,and 0.9 were prepared by simple precipitation method using AgBr as the photoactive component and acidified CNH as support.The results show that AgBr is the most homogeneous dispersion on the CNH support when m(AgBr)/m(CNH)=0.5,AgBr has a particle size of 30～60 nm and has the highest photocatalytic degradation activity of RhB,the photocatalytic activity of CNH was 3.6 times higher than that of the only CNH.3.The composite photocatalyst Ag/g-C3N4 was prepared by silver nitrate and melamine as the raw materials,and the nano-silver supported composite photocatalyst Ag/g-C3N4 was prepared by solvothermal method,the photoreduction method and the calcination reduction method respectively.The results show that at the fixed ratio,the Ag/g-C3N4 composite photocatalyst prepared by the light reduction method has the highest photocatalytic activity of RhB activity,in which the Ag particle size is about 14nm and homogeneously dispersed on the g-C3N4 support.The Ag/g-C3N4 composite photocatalyst with different ratios of 5%,10%,15%,20%,25%and 30%was prepared by light reduction method.The photocatalytic degradation of RhB showed that the ratio of 25%Ag/g-C3N4 has the highest photocatalytic activity,and the degradation yield is up to 75%during 1.5 h under visible light,and the stability of 5 times is better than 60%. |
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