Facile synthesis of sulfur and nitrogen codoped graphene quantum dots for optical sensing of Hg and Ag ions

Facile and simple sulfur and nitrogen co-doped graphene Quantum Dots (S, N-GQDs) were fabricated via. calcination. UV-vis. spectrum reveals two peaks originates due to the transition from n and pi to pi* of the luminescent material. The photoluminescence emission of S, N-GQDs has been quenched upon addition of Hg and Ag ions. The higher affinity of sulfur for Hg and Ag ions assigned selectivity to the sensing protocol which was confirmed from the absence of any interference of the competitive ions. The S, N-GQDs could sense Hg and Ag ions as low as 9.14 mu M and 12.90 mu M respectively.