zeolite-Y/g-C3N4 composite with enhanced photocatalytic activity for dye degradation and nitrogen fixation

摘要

The zeolite-Y/g-C3N4 composites were successfully synthesized by a facile hydrothermal method. The composition, structure and optical properties of the composites were characterized by infrared spectroscopy, X-ray diffraction, UV-Vis diffuse reflectance spectroscopy and other spectral techniques. The as-prepared zeolite-Y/g-C3N4 composite exhibits remarkably enhanced photocatalytic activity for organic dye degradation and nitrogen fixation under visible light irradiation. The optimal hybrid catalyst (YCN-50) shows good photocatalytic activity for methylene blue degradation. The degradation kinetic constant is 26.6 times higher than that of g-C3N4. Photocatalytic degradation of other organic dyes including malachite green, methyl orange and rhodamine B was also studied for comparison. For the photocatalytic nitrogen fixation, the ammonium production rate of zeolite-Y/g-C3N4 composite is 62.7 mu mmol g(-1) h(-1) under the optimal condition, which is 62.7 times higher than that of pure g-C3N4. The high photocatalytic performance of zeolite-Y/g-C3N4 composite is due to the combination of g-C3N4 and zeolite-Y effectively improving the specific surface area and reducing the recombination rate of photogenerated carriers. The zeolite-Y/g-C3N4 composite also shows good photostability and reusability based on recycling experiments. Trapping experiment was also performed to find the responsible radical species for the degradation. The mechanism of dye degradation and nitrogen fixation in the presence of zeolite-Y/g-C3N4 was also discussed.