Photocatalytic technology, as one of the most promising environmental remediation tools, has a wide range of applications in the field of removing antibiotic-based pollutants from wastewater. Therefore, to obtain efficient green and inexpensive photocatalysts, a p–n type Bi₂MoO₆/CuS composite photocatalyst modified by lignin carbon quantum dots (CQDs) was successfully prepared by solvothermal in situ co-precipitation in this study. It was used to achieve efficient photocatalytic degradation of tetracyclic hydrochloride antibiotics (TCH). The composites were systematically characterized by XRD, FTIR, XPS, SEM, TEM, EIS, nitrogen adsorption–desorption test, and UV–Vis DRS regarding crystal structure, microscopic morphology, and photoelectric properties. The results showed that the prepared samples had good crystallinity and high purity. The photocatalytic degradation experiments further demonstrated that the Bi₂MoO₆/CuS composites modified by CQDs exhibited excellent photocatalytic activity compared to Bi₂MoO₆ and CuS monomers wherein CQDs@Bi₂MoO₆/CuS 2 was the most effective, with a TCH removal of 96.98% and a degradation rate constant (K) of 0.04405 min⁻¹ after 60 min of light exposure. The TCH removal could be maintained at 78.25% after four cycles. The ESR and LC–MS experiments demonstrated that h⁺ and ·O₂⁻ were the main active substances for photocatalytic degradation of TCH. This work provides an efficient catalyst for TCH removal and offers new ideas for applying p–n heterojunction composites in photocatalysis.

光催化技术作为最有前途的环境修复工具之一，在去除废水中抗生素类污染物领域有着广泛的应用。因此，为了获得高效、绿色、廉价的光催化剂，本研究采用溶剂热原位共沉淀法成功制备了木质素碳量子点（CQDs）改性的p - n型Bi ₂ MoO ₆ /CuS复合光催化剂。它被用来实现四环盐酸盐抗生素（TCH）的高效光催化降解。通过 XRD、FTIR、XPS、SEM、TEM、EIS、氮气吸附-脱附测试和 UV-Vis DRS 系统地表征了复合材料的晶体结构、微观形貌和光电性能。结果表明，所制备的样品结晶度好、纯度高。光催化降解实验进一步表明，与Bi ₂ MoO ₆和CuS单体相比，CQDs改性的Bi 2 MoO 6 /CuS复合材料表现出优异的光催化活性，_其中CQDs _@ Bi ₂ MoO ₆ /CuS 2 最有效，具有TCH去除效果光照射 60 分钟后，降解率常数 (K)为 96.98%，降解速率常数 ( K ) 为 0.04405 min ^-1 。 4个循环后TCH去除率可维持在78.25%。 ESR和LC-MS实验表明h ⁺和·O ₂ ^-是TCH光催化降解的主要活性物质。该工作为TCH去除提供了一种高效的催化剂，并为p - n异质结复合材料在光催化中的应用提供了新思路。