Red fluorescent carbon dots for sensitive and selective detection and reduction of Au3+

Simultaneous detection and reduction of Au3+ in contaminated water is extremely desirable. Herein, we synthesized red fluorescent carbon dots (CDs) for Au3+ detection with dual colorimetric and fluorescent spectral response within 2 min. The CDs showed high sensitivity and selectivity towards Au3+ with a low detection limit of 29 nM. Further, CDs selectively reduce Au3+ to Au0 via redox reaction between the thioether group on the surface of CDs and Au3+. Accordingly, CDs were effectively utilized to detect and extract Au3+ without interference from other metal ions.