Abstract: A series of g-C3 N4/ZnCr-LDH nanocomposites with different ratios were successfully prepared by in situ synthesis , the morphology , structure and photoelectrochemical properties were systematically studied, and the catalytic performance of the degradation of methyl orange was carried out under visible light.The results show that the combination of g-C3 N4 and ZnCr-LDH can enhance the absorption intensity of visible light , effectively inhibit the photo-electron-hole recombination , and improve the activity of the composite photocatalyst .The efficiency of degradation of methyl orange by 0.92CN/LDH composite photocatalyst is 97; at 2 h, which is 2 times higher than that of pure g-C3 N4 .Finally, after 5 cycles of continuous experiments , it was found that the degradation activity of the composite photocatalyst is still above 80;, which indicate that the composite has good stability .

Key words: A series of g-C3 N4/ZnCr-LDH nanocomposites with different ratios were successfully prepared by in situ synthesis , the morphology , structure and photoelectrochemical properties were systematically studied, and the catalytic performance of the degradation of methyl orange was carried out under visible light.The results show that the combination of g-C3 N4 and ZnCr-LDH can enhance the absorption intensity of visible light , effectively inhibit the photo-electron-hole recombination , and improve the activity of the composite photocatalyst .The efficiency of degradation of methyl orange by 0.92CN/LDH composite photocatalyst is 97; at 2 h, which is 2 times higher than that of pure g-C3 N4 .Finally, after 5 cycles of continuous experiments , it was found that the degradation activity of the composite photocatalyst is still above 80;, which indicate that the composite has good stability .