<p>Photocatalysis plays a crucial role in addressing both environmental remediation and energy generation challenges. One notable class of photocatalysts is carbon quantum dots (CQDs), which exhibit enhanced electron transfer capabilities, up-conversion of photoluminescence, and non-toxic characteristics. CQDs can act independently as photocatalysts or be incorporated into composite materials to enhance their effectiveness. These nanomaterials have emerged as a valuable tool for tackling significant environmental issues due to their unique optical, chemical, and electronic properties. Their fluorescence abilities make CQDs particularly useful for detecting microplastics across various environmental settings. Furthermore, their capacity to interact with gas molecules enables the development of efficient gas sensors for monitoring air pollutants. In the context of water remediation, CQDs serve multiple roles, functioning as adsorbents, photocatalysts, and electrochemical sensors to remove heavy metals, organic pollutants, and other contaminants from water sources. Despite the advancements in CQD research, several challenges remain. Key issues include the development of scalable and environmentally friendly synthesis methods, enhancing selectivity and sensitivity, and ensuring long-term stability of these materials. Future research should prioritize overcoming these obstacles while also exploring new applications for CQDs in environmental remediation. By leveraging the potential of CQDs, we can work towards a cleaner and more sustainable future.</p>