Translation of the abstract of a chemical thesis摘要光催化是分解水制备氢气的反应可以将太阳能这种获取成本低的可再生能源转化为方便存储、运输和利用的化学能为解决当前全球环境保护和能源利用面临的诸多困难提供了许多思路因而备受关注。其中一种途径即通过构建合理的催化剂体系应用Z型异质结进行分解水的产氢半反应它的可行性已被越来越多的研究所证明。但具体如何构建和

Photocatalysis is a reaction that decomposes water to produce hydrogen gas, which can convert low-cost renewable energy sources such as solar energy into chemical energy that is convenient for storage, transportation, and use. This provides many ideas for solving the many difficulties facing global environmental protection and energy utilization, and thus has attracted much attention. One approach is to use a reasonable catalyst system and apply the Z-type heterojunction to the hydrogen evolution reaction of water splitting, which has been increasingly proven feasible by more and more research. However, how to construct and improve the catalyst system still needs further study.

g-C3N4 has the characteristics of being environmentally friendly, easy to obtain, and excellent stability in water, making it suitable as a catalyst for the hydrogen evolution reaction in water. This thesis aims to improve the catalytic performance of the hydrogen evolution reaction by loading different mass ratios of phthalocyanine copper dyes on the surface of two-dimensional g-C3N4 catalysts and to explore the optimal mass ratio and mechanism after loading.

In this study, two-dimensional g-C3N4 materials were first prepared by secondary calcination, and their original catalytic performance for the hydrogen evolution reaction was measured, followed by optimization of the catalyst material preparation method. Then, ultrasound stirring and insulation stirring were used in combination to load phthalocyanine copper dyes on the surface of two-dimensional g-C3N4 semiconductor materials in different mass ratios to obtain different phthalocyanine copper/g-C3N4 Z-type heterojunction systems. The structure and optical properties of the original catalyst and the catalyst after loading were preliminarily characterized by X-ray powder diffraction (XRD), ultraviolet-visible absorption spectroscopy (UV-Vis), and infrared spectroscopy (IR). The results showed that the sample with secondary calcination had an average hydrogen evolution rate of 592.54 μmol·g-1·h-1, a 122% increase compared to the sample with primary calcination (266.43 μmol·g-1·h-1), possibly due to significant two-dimensionalization of the material, resulting in an increase in surface area and thus an increase in the number of catalytic sites. Compared with g-C3N4 without loaded dyes, the catalytic performance of g-C3N4 loaded with phthalocyanine copper in different mass ratios has changed to varying degrees. The sample with 2 wt.% mass ratio showed the most significant improvement in performance, with a hydrogen evolution rate of 1428.06 μmol·g-1·h-1, 2.41 times that of the sample without loaded dyes. Finally, this thesis attempts to analyze the mechanism of the improvement effect of phthalocyanine copper dyes on the catalyst after loading, namely the dye sensitization mechanism. This work provides some reference and inspiration for further improving the hydrogen evolution performance of the phthalocyanine copper/g-C3N4 system.