Green preparation of palm powder-derived carbon dots co-doped with sulfur/chlorine and their application in visible-light photocatalysis.

To exploit photocatalytic performance is one of the worthiest efforts for expanding the application of carbon dots (CDs) owing to their low-cost starting materials, facile preparation and simple operation without secondary pollution. Herein, novel biomass-based CDs (Bio-CDs) were successfully synthesized from waste palm powders by using one-step hydrothermal method under the facilitation of thionyl chloride on carbonization process and doping effect. The resultant Bio-CDs exhibited quasi-spherical shape with an average size of 3.54 nm and displayed blue-emissive fluorescence with excitation-dependent behavior. Benefiting from the S and Cl co-doped structure and small size effect, the synthesized Bio-CDs possessed high photocatalytic activity towards the degradation of organic dyes under visible light. The degradation of the Rhodamine B was nearly 71.7%, while the Methylene Blue was almost decomposed completely (ca. 94.2%), which make the Bio-CDs to be a hopeful candidate as photocatalyst for the reduction of organic pollutants.