高效光催化分解水制氢：基于酞菁铜修饰的二维g-C3N4催化剂研究

Abstract:

The photocatalytic decomposition of water to produce hydrogen, using solar energy as a low-cost and renewable energy source, has attracted attention as a way to alleviate the many difficulties faced in global environmental protection and energy utilization. The main conversion route is through the construction of a reasonable catalyst system, using the Z-type heterojunction to carry out the hydrogen production reaction of water decomposition. How to improve the catalyst system in a reasonable way still needs further research.

g-C3N4 has the characteristics of environmental friendliness, easy access, and excellent stability in water, making it suitable as a catalyst for hydrogen production reaction in water. In this thesis, the catalytic performance of the hydrogen production reaction will be improved by solidifying different mass ratios of phthalocyanine copper dyes on the surface of pre-prepared two-dimensional g-C3N4 catalysts. The optimal mass ratio and mechanism of the solidified catalyst will be explored.

Firstly, two-dimensional g-C3N4 catalyst materials were prepared by secondary calcination method. By measuring the original catalytic performance of hydrogen production, the preparation method of the catalyst material was optimized. Then, ultrasound stirring and insulation stirring were used to prepare phthalocyanine copper-g-C3N4 catalyst system solidified on the surface of two-dimensional semiconductor materials with different mass ratios. The structure and optical properties of the original catalyst and the solidified catalyst with different mass ratios were preliminarily characterized by X-ray powder diffraction (XRD), UV-visible absorption spectroscopy (UV-Vis), and infrared spectroscopy (IR). The results showed that compared with the rough product after primary calcination, the g-C3N4 obtained after secondary calcination became significantly two-dimensional, and the increase in surface area brought about an increase in the number of catalytic sites, leading to an improvement in catalytic hydrogen production performance. Compared with the untreated g-C3N4, the catalytic hydrogen production performance of phthalocyanine copper-g-C3N4 solidified with different mass ratios was improved to varying degrees. Among them, the sample with 2% mass ratio had the most significant performance improvement, increasing from 2714 μmol·g-1·h-1 to 2714 μmol·g-1·h-1, which was 20 times that of the original sample. Finally, this thesis attempts to analyze the mechanism of the improvement of the catalyst after the solidification of phthalocyanine copper dye-the dye sensitization mechanism. This work provides some reference significance for further improving the hydrogen production performance of the phthalocyanine copper-g-C3N4 system.

Keywords: Phthalocyanine copper, g-C3N4, Photocatalytic water splitting