Influence of phyto-derived nitrogen doped carbon dots from the seeds of Azadirachta indica on the NaBH4 reduction of Safranin-O dye

Nitrogen doped biogenic carbon dots have become promising candidates for diverse applications in the field of environment and medicine. In the present work, an eco-friendly and hydrothermal route was employed to synthesize highly fluorescent phyto derived nitrogen doped carbon dots (PDNCDs) from neem seeds. The prepared PDNCDs exhibited high water dispersity, excellent optical and fluorescent properties. The size of the PDNCDs was about 2.5 nm as given by the HR-TEM results. The PDNCDs were demonstrated to have high stability through zeta potential and TGA measurements. Their amorphous nature was explained from the results of XRD. The XPS, FT-IR and EDS measurements correlated well with each other in the characterization of functional moieties and elemental proportions of the PDNCDs. Raman spectroscopic and SAED results confess the graphitic nature of the PDNCDs. Studies with different solvents indicated that the properties of the PDNCDs can be fine-tuned. Finally, PDNCDs were found to have profound influence as catalyst in the NaBH4 reduction of Safranin-O, a phenazine dye, with the reduction completed within 6 min. The catalytic influence of PDNCDs could be elucidated on the basis of LangmuirHinshelwood mechanism.