| Efficient photocatalytic materials have important research status and application prospects in photocatalytic technology.g-C3N4 photocatalyst has attracted much attention due to its simple synthesis method,low toxicity,and suitable band gap.However,due to the poor separation ability of carriers and small surface area,it cannot be widely used.To solve these matters,in this paper,a method of in situ self-assembly was used to grow dual cocatalysts Mo S2 and Co Sx（a derivative of ZIF67）on the surface of flake g-C3N4（CN）.Co Sx/Mo S2/CN double heterojunction composites with large specific surface area,high visible light utilization efficiency,and fast electron transfer rate were successfully prepared.The main research is as follows:The two kinds of cocatalysts form a double hetrojunction with CN,and the synergistic effect among the three will promote the separation of carriers,expand the specific surface area,improve light absorption,and therefore improve the photocatalytic ability of the composite.The test results of photocatalytic hydrogen evolution show that5%Co Sx/Mo S2/CN-2 photocatalyst has the best performance,with a hydrogen evolution rate of 9800μmol·h-1·g-1 is 6.5 times,46 times,and 98 times as much as CN,Mo S2,and Co Sx,respectively.DFT simulated and calculated the energy band structures of CN,Mo S2,and Co Sx,inferring that the ternary system follows the charge transfer mechanism of type I-II heterojunction,and deeply explored the reaction mechanism of photocatalytic hydrogen evolution of 5%Co Sx/Mo S2/CN samples.The subject further studied the photocatalytic degradation of organic dyes using5%Co Sx/Mo S2/CN-2 samples and the effects of various factors on the degradation rate.The results indicated that the best experimental factors for photocatalytic degradation of organic dye methylene blue（MB）using ternary composite materials under visible light were as follows:the initial concentration of MB was 5 mg/L,the mass of catalyst was 10 mg,and the PH=7.The intermediate products obtained from the dissociation of MB during the degradation procedure were detected by liquid chromatography mass spectrometry,the degradation process and reaction mechanism were analyzed.In order to explore the pragmatic value of the catalyst,5%Co Sx/Mo S2/CN-2 was used to degrade 5 mg/L of MB under vis-light.The results manifested the degradation rate can achieve 99.85%under 3.5hours of light,indicating that the catalyst had great practicality.In the meantime,after 5cycles of tests,the catalyst has good stability. |
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