Vol.:(0123456789) Research on Chemical Intermediates https://doi.org/10.1007/s11164-023-05046-y 1 3 Rational construction of metal‑free carbon quantum dots/graphitic carbon nitride composite photocatalyst for mitigation of organic containments Kasirajan Prakash 1  · G. Lakshmi 1  · S. Muralidharan 2  · M. Arunpandian 1  · Sundaram Ganesh Babu 3 Received: 30 March 2023 / Accepted: 5 June 2023 © The Author(s), under exclusive licence to Springer Nature B.V. 2023 Abstract In this (scenario) research work, the CQDs@g-C 3 N 4 two-step-scheme nanocom- posite was fabricated by a simple two-step hydrothermal/calcination process. The crystalline phase and morphological features of the materials were investigated by P-XRD, SEM, EDAX, and TEM. The designed CQDs@g-C 3 N 4 nanocomposite was fruitfully formed, and the improved light absorption capability was tested with the photocatalytic activity of (Rhodamine B) RhB and (Ofoxacin) OFL. The CQDs@g- C 3 N 4 nanocomposite shows enhanced activity in the degradation of RhB, and OFL and corresponds to a low recombination rate of charge carriers. Under optimized experimental conditions, the photocatalytic activities of pollutants (RhB & OFL) over CQDs@g-C 3 N 4 can accomplish 94.3 and 99.5% within 30 and 60 min irra- diation with visible light. The trapping experiments exhibited that O ⋅- 2 , ⋅OH, and intermediate mineralized compounds were involved in the catalysis process. Fur- thermore, the CQDs@g-C 3 N 4 photocatalyst has remarkable storage stability after * Kasirajan Prakash prakashchemist88@gmail.com * Sundaram Ganesh Babu ganeshbabu.s@vit.ac.in G. Lakshmi lakshmi.g@psr.edu.in S. Muralidharan muralidharan@psr.edu.in M. Arunpandian arunpandianttl26@gmail.com 1 Department of Chemistry, PSR Engineering College, Sivakasi, Tamil Nadu 626140, India 2 Department of Chemistry, Nanomaterials Laboratory, Kalasalingam Academy of Research and Education, Krishnankoil 626126, India 3 Department of Chemistry, School of Advanced Sciences, Vellore Institute of Technology, Vellore, Tamil Nadu 632014, India