The development of novel semiconductor with highly efficient photocatalytic activity for completely degrading organic pollutants in the aquatic environment is a dominating goal of modern chemistry. Herein, a novel composite with excellent photocatalytic activity was firstly synthesized by loading small size of ZnSe quantum dot (QDs) and nano-Ag onto the surface of the bulk g-C₃N₄ (CN). The novel composite (ZnSe-Ag/CN) was used to degrade Ceftriaxone sodium in the aquatic environment at low concentrations under visible light irradiation, and the 7%-ZnSe-Ag/CN composite displayed superior photocatalytic activity, approximately 89.24% of Ceftriaxone sodium has been degraded under visible light irradiation for 90 min, which was approximately 10.14-folds, 2.72-folds, 2.09-folds and 1.39-folds higher than pure ZnSe QDs, CN, 7%-Ag/CN and 5%-ZnSe/CN sample, respectively. Based on the adsorption test, the UV–vis diffuse reflectance spectra (DRS), the N₂ adsorption–desorption isotherm, the photoluminescence spectra, the transient photocurrent response and the electrochemical impedance spectroscopy (EIS) measurements, the enhanced photocatalytic activity of the ZnSe-Ag/CN composite could be attributed to the excellent adsorbability, expansion of the light-harvesting scope, as well as the efficient separation of photogenerated electron-hole pairs. Meanwhile, the ZnSe-Ag/CN composite could produce a large amount of the hydroxyl radicals (OH) during the photocatalytic degradation process. Furthermore, a possible pathway of Ceftriaxone sodium degradation was proposed according to the detailed analyses of the produced intermediates to better understand the reaction process. Therefore, this work offers a new strategy for designing novel photocatalyst with excellent photocatalytic activity to remediation of water contamination.

开发具有高效光催化活性以完全降解水生环境中有机污染物的新型半导体是现代化学的主要目标。本文中，首先通过将小尺寸的ZnSe量子点（QDs）和纳米Ag负载到块状gC ₃ N ₄的表面上，合成了具有优异光催化活性的新型复合材料。（CN）。新型复合材料（ZnSe-Ag / CN）在可见光照射下以低浓度降解水环境中的头孢曲松钠，而7％-ZnSe-Ag / CN复合物表现出优异的光催化活性，约占头孢曲松钠的89.24％。在可见光照射下降解90分钟，比纯ZnSe QD，CN，7％-Ag / CN和5％-ZnSe / CN高出约10.14倍，2.72倍，2.09倍和1.39倍样本。根据吸附测试，紫外可见漫反射光谱（DRS），N ₂吸附-解吸等温线，光致发光光谱，瞬态光电流响应和电化学阻抗谱（EIS）测量，ZnSe-Ag / CN复合材料的增强的光催化活性可归因于出色的吸附能力，扩大了光收集范围，以及有效分离光生电子-空穴对。同时，ZnSe-Ag / CN复合材料会产生大量的羟基自由基（OH）在光催化降解过程中。此外，根据对产生的中间体的详细分析，提出了头孢曲松钠降解的可能途径，以更好地了解反应过程。因此，这项工作为设计具有优异光催化活性以修复水污染的新型光催化剂提供了新的策略。