Photocatalytic efficiency of carbon quantum dots/TiO2: a systematic literature review

Abstract Semiconductor photocatalysis has emerged as a highly dynamic research field with broad applications in photochemistry, electrochemistry, and environmental science. This review focuses on the photocatalytic behavior of carbon quantum dots (CQDs) and titanium dioxide (TiO₂), two promising materials for pollutant photodegradation. CQDs exhibit remarkable properties, including high surface area, strong visible-light absorption, and excellent photostability, whereas TiO₂ is an efficient semiconductor capable of generating reactive radicals upon photoexcitation. A systematic literature review (SLR) was conducted to analyze 94 peer-reviewed studies retrieved from major scientific databases, including ScienceDirect, Scopus, Web of Science, SpringerLink, Wiley Online Library, the Royal Society of Chemistry (RSC), ACS Publications, and IOPscience. The analysis revealed that CQDs/TiO₂ demonstrate significantly enhanced photocatalytic activity in applications such as environmental remediation and bacterial inactivation. However, limitations remain, including challenges related to visible-light utilization, excessive CQD loading, and insufficient investigation of long-term stability and scalability under real environmental conditions. In summary, this review highlights the potential of CQDs/TiO₂ in environmental remediation and provides a comprehensive overview of their mechanisms, efficiency, and existing challenges. Future research should focus on structural optimization and long-term stability to fully harness the potential of this photocatalyst.