As a solid-state electron medium of composite photocatalysts, carbon dots (C-dots) increase the transition process of photogenerated carriers and inhibit their rapid recombination. In this work, novel and efficient Z-scheme heterojunction BiVO₄/C-dots/g-C₃N₄ photocatalysts with C-dots as the photoelectron transfer center were designed. FTIR, HRTEM, TEM, XRD and PL were used to investigate the physical and chemical properties of the photocatalysts. Due to the up-conversion photoluminescence characteristics of the carbon dots, the BiVO₄/C-dots/g-C₃N₄ photocatalysts exhibit significant interfacial charge transfer capability and a broader visible absorption range. In addition, the photocatalytic activity of the photocatalysts was improved by changing the doping amount and optimizing the synthesis conditions. As a result, the BiVO₄/C-dots/g-C₃N₄ composites showed remarkable degradation efficiency of minocycline hydrochloride (Mino-HCl) and Rhodamine B (RhB) under near-visible LED light. Furthermore, the photodegradation efficiency of the BiVO₄/C-dots/g-C₃N₄-40 photocatalyst was conspicuously improved over those of pure BiVO₄, g-C₃N₄ and the composites with other content ratios. The comparative experiment also proved that the introduction of carbon dots can enhance the performance of the photocatalyst. Finally, the possible catalytic mechanism was explored via a free radical capture experiment for the active substances, and the excellent photostability and reusability of the BiVO₄/C-dots/g-C₃N₄ composites were proved through three cycles of experiments.

中文翻译：

---

超声辅助合成BiVO4 / C-dots / g-C3N4 Z-方案异质结光催化剂降解盐酸米诺环素和若丹明B的工艺及机理研究

作为复合光催化剂的固态电子介质，碳点（C点）增加了光生载流子的过渡过程并抑制了它们的快速重组。本文设计了以C点为光电子转移中心的新颖高效的Z型异质结BiVO ₄ / C点/ gC ₃ N ₄光催化剂。FTIR，HRTEM，TEM，XRD和PL用于研究光催化剂的物理和化学性质。由于碳点的上转换光致发光特性，BiVO ₄ / C-点/ gC ₃ N ₄光催化剂显示出显着的界面电荷转移能力和更宽的可见吸收范围。另外，通过改变掺杂量和优化合成条件，提高了光催化剂的光催化活性。结果，BiVO ₄ / C-dots / gC ₃ N ₄复合材料在近可见LED灯下显示出盐酸米诺环素（Mino-HCl）和若丹明B（RhB）显着的降解效率。此外，与纯BiVO ₄，gC ₃ N _4相比，BiVO ₄ / C-dots / gC ₃ N ₄ -40光催化剂的光降解效率显着提高。以及其他含量比的复合材料。对比实验还证明，引入碳点可以增强光催化剂的性能。最后，通过自由基捕获实验研究了活性物质的可能催化机理，并通过三个实验周期证明了BiVO ₄ / C-dots / gC ₃ N ₄复合材料的优异的光稳定性和可重复使用性。