A novel Zn-doped CHA zeolite coupled CDs for photocatalytic nitrogen fixation

The construction of zeolite/semiconductor was proved to be one of the effective ways to improve the photocatalytic performance. In this paper, CDs@Zn-CHA/CN was prepared by hydrothermal method, and a synergistic interaction was formed between CDs@Zn-CHA and CN to enhance the photocatalytic nitrogen fixation activity. The photoelectric properties characterization and XPS and in situ IR results indicated that CDs, Zn-CHA and CN formed a charge transfer interface, which improved the separation of photogenerated carriers and greatly enhanced the nitrogen fixation efficiency. Nitrogen is adsorbed by Zn-CHA with microporous structure and activated by contact with Zn sites on CHA. CN has a good visible light response and provides photogenerated carriers under visible light irradiation. CDs act on the interfacial charge transfer between Zn-CHA and CN, promoting the transfer of photogenerated electrons to the nitrogen adsorbed by Zn-CHA and accelerating the dissociation of NN, thus increasing the yield of NH3. Compared with CDs@Zn-CHA and CN, 10% CDs@Zn-CHA/CN achieved 5.82 and 2.99 times of nitrogen fixation yield, respectively. Furthermore, the higher hydrophobicity of CDs@Zn-CHA/CN was found by contact angle measurement, which provided more abundant three-phase contact points for the reaction process. This study provides new ideas and directions for the design of photocatalyst.