Microwave-assisted green synthesis of Pithecellobium dulce seed pods derived fluorescent carbon dots for Pd2+ detection

A simple and ecofriendly microwave-aided pyrolysis method is developed to synthesize carbon dots (CDs) using Pithecellobium dulce seed pods as the carbon source. UV-Visible, fluorescence, FTIR, XRD, TEM, and XPS were used to characterize the synthesized CDs. Using this method, highly luminous CDs can be manufactured with particles as small as 4 nm. A quantum yield of 9.73% was estimated from 425 nm emission at 335 nm excitation, using quinine sulfate as a reference (quantum yield 54%). Various conditions, including pH, high ion strength, continuous radiation, and storage, were encountered by these CDs. These were showed high aqueous dispersibility, excitation-dependent fluorescence emission, and remarkable durability. CDs emissions are effectively quenched by Pd2+; therefore, the synthesized CDs were preferred as a highly sensitive and selective probe for the detection of Pd2+ ions. A detection limit of 0.37 mu M can be achieved, and the linear range was from 2 to 50 mu M. Moreover, the probe demonstrated good precision and was effective for detecting Pd2+ in real water samples without interference.