Nanocatalytic and antimicrobial potency of CQD@Pd nanoparticles: Experimental and theoretical approach

A single-pot approach has been developed for the fabrication of novel heterogeneous nanocatalyst of carbon quantum dots doped palladium (CQD@Pd-NPs) nanoparticles. Herein, Aegle marmelos fruit extract was utilized as a reducing and capping agent for the fabrication of CQD@Pd-NPs. Synthesis of metallic nanoparticles through green chemistry route is environment beneficial technology owing to its low cost and ecological compatibility. The formation of CQD-NPs and CQD@Pd-NPs was confirmed with high-end sophisticated techniques and theoretical studies. The computational analysis revealed a discernible decrease in the band gap value (Egap = ELUMO - EHOMO) from 0.08 eV to 0.03 eV upon the introduction of Pd atoms into carbon quantum dots (CQDs). Therefore, computational data also authenticates the stability of the CQD@Pd-NPs nanocatalyst which was predominantly supported by electrostatic interaction between Pd and CQDs. The developed nanocatalyst has vouched for an effective candidature in the Suzuki-Miyaura and Mizoroki-Heck coupling reactions with a superior selectivity for product formation. The excellent antibacterial properties against E. coli and S. aureus were further supported by visualizing bacterial growth, inhibition zone, FESEM results and molecular docking studies. Moreover, the nanocatalyst displayed facile separation from the reaction system and showcased efficient recyclability with minimal activity loss. This further supports an effective potential over existing commercial catalysts and holds immense future prospective in industrial applications.