Water‐Soluble and Lowly Toxic Sulphur Quantum Dots

Here, a new class of quantum dots, that is, sulphur quantum dots (SQDs), which are synthesized by the phase interfacial reaction, is reported. The prepared SQDs are monodisperse with a narrow size distribution (average 1.6 nm in size), excellent aqueous dispersibility, ultrahigh photostability, and lowly toxicity. Because of abundant oxidized sulphur species on the surface of SQDs, the incorporation of TiO 2 with SQDs results in a synergistic effect for the TiO 2 ‐based photocatalysts offering more effective environmental applications. It is demonstrated that SQDs‐TiO 2 nanocomposite can enhance the photocatalytic activity of producing hydrogen (enhancement factor for 191) in methanol‐water system. The SQDs also can used as fluorescent probe for highly selective quantitative detection Fe 3+ in an aqueous solution contained various metal ions.