Green production of fluorescent carbon quantum dots based on pine wood and its application in the detection of Fe3+

Carbon quantum dots (CQDs) have novel applications as fluorescent nanomaterials in various fields. In this study, a green hydrothermal carbonisation (HTC) method is proposed to produce CQDs from pine wood (P-CQDs). The P-CQDs exhibited excellent fluorescence characteristics, with the optimal excitation wavelength being 330 nm and a corresponding emission wavelength of 447 nm. A blue light emission under ultraviolet light was observed and a typical graphene structure was seen in the HR-TEM images with a fringe spacing of 0.21 nm. Moreover, the mechanism of P-CQD formation during the HTC process was proposed. It was observed that P-CQDs demonstrated an aromatic polymer structure rich in oxygen-containing groups. This is because of the condensation, chain breaking, and chain forming reactions occurring among the hydrolytic products of the cellulose , hemicellulose , and lignin in pine wood. The fluorescence quenching results indicated that the P-CQDs selectively detected Fe 3+ in an aqueous phase . This implies that these CQDs have broad application prospects for Fe 3+ detection. More importantly, this signifies that the large-scale and low-cost production of CQDs and Fe 3+ sensors will now be possible.