结合计算化学，对现有的物理化学实验教材中的“偶极矩测定”实验进行拓展，通过势能曲线探究乙酸乙酯的可能结构，并将偶极矩计算与结构相联系，同时考虑不同条件对偶极矩计算结果的影响。实验能够从微观角度对宏观现象进行辨析，并帮助理解结构与性质之间的关系。整个实验坚持“教-学-评”一体化，实验设计与课程思政有机融合，通过案例分享、知识探究，可有效激发学习兴趣和热情，培养思辨的科学研究能力。

Photoelectrochemical water splitting using semiconductor materials is one of the most promising methods for converting solar energy into chemical energy. Among the commonly used semiconductors, p-type CuBi₂O₄ is considered one of the most suitable photocathode materials and can allow a theoretical photocurrent density of about 20 mA·cm⁻² for photoelectrochemical water splitting. However, due to severe charge carrier recombination, the obtained photocurrent density is much lower than the theoretical value. Highly efficient photoelectrochemical performance relies on fast charge carrier separation and transport, and prompt reaction kinetics. In this study, we report the development of a polyoxometalate-modified CuBi₂O₄/Mg-CuBi₂O₄ homojunction photocathode to improve both the bulk and interfacial charge carrier transport in the photocathode. For the bulk of the photocathode, the built-in electric field originating from the CuBi₂O₄/Mg-CuBi₂O₄ homojunction promotes the migration of photo-excited electrons on the conduction band from pure CuBi₂O₄ to Mg-doped CuBi₂O₄. Additionally, the electric field facilitates the transfer of holes from the valence band of Mg-doped CuBi₂O₄ to pure CuBi₂O₄. This directional transfer of both photo-excited electrons and holes plays a significant role in promoting separation and suppressing the recombination of the charge carriers. On the surface of the photocathode, the reduced polyoxometalate co-catalyst Ag₆[P₂W₁₈O₆₂] (AgP₂W₁₈) was used as a proton sponge to accelerate surface reaction kinetics and suppress carrier recombination. These synergistic effects improved the photo-generated charge carrier transfer and reaction kinetics. As a result, the novel photocathode displayed excellent photoelectrochemical properties, and the photocurrent density was observed to be −0.64 mA·cm⁻² at 0.3 V vs. RHE, which is better than that of −0.39 mA·cm⁻² for a pure photocathode. Furthermore, the novel photocathode had an applied bias photon-to-current efficiency (ABPE) higher than 0.19% at 0.3 V vs. RHE. In contrast, the pure photocathode had an ABPE of ~0.12% under the same conditions. Additionally, when H₂O₂ was used as an electron scavenger, the photocurrent density was −3 mA·cm⁻² at 0.3 V vs. RHE, which is an improvement of approximately 1.5 times compared to the pure photocathode. Furthermore, the charge separation and charge injection efficiency of the novel photocathode were significantly improved compared with the pure photocathode. The experimental results conclusively indicate that the formation of the CuBi₂O₄/Mg-CuBi₂O₄ homojunction and AgP₂W₁₈ modification played a significant role in the improved performance of the CuBi₂O₄ photocathode. The performance of the novel photocathode was comparable with the results reported in previous studies, demonstrating its promising potential in real applications.