Citrus sinensis agro-waste peels mediated CQDs-Ag nanocomposite potentiates numerous applications

Abstract In chasing green nanoscale research, the reductive efficacy of a typical agro-waste product of the food industry, namely, orange peels, has been investigated to synthesize carbon quantum dots silver nanocomposites [CQDs-Ag NCs] via a greener route. CQDs-Ag NCs are having great importance for their diverse applications in the chemical, medical, biological and agricultural sector including their role in chemical reactions, sensing, catalysis, as nanopesticides or nanofertilizers, antifungal, antimicrobial, anti-bacterial, and antioxidant activity. The synthesis of CQDs-Ag NCs was conducted mainly in 4 steps, namely, composition of orange peels fine powder, phytochemical screening of precursor orange peel extract, orange peel derived fluorescent CQDs by green and facile microwave-assisted method and further biosynthesis of CQDs-Ag NCs. Structural characterization revealed that CQDs-Ag NCs exhibit cubic crystallinity belonging to Ag nanoparticles with few humps belonging to CQDs. The average sizes of orange peels mediated carbon quantum dots were around 5–8 nm. Microstructural analysis of CQDs-Ag NCs showed polydispersed grains with an average size of 15–20 nm. The agar well-diffusion test demonstrated that these nanocomposites are a promising material for antibacterial agents. This assertion was supported by the evidence showing that the diameter of the created clear zone ranges from 12–14 mm. Thus, nanotechnology (CQDs-Ag NCs) can be considered to have great potential in precision agriculture and bactericidal applications.