Carbon quantum dots-doped CdS microspheres with enhanced photocatalytic performance

• Carbon quantum dots-doped CdS microspheres were synthesized using glutathione as a template.
• The CQDs/CdS shows high and steady photocatalytic activity.
• CQDs can efficiently trap electrons and hinder the recombination of electrons and holes.

Carbon quantum dots (CQDs)-doped CdS (C/CdS) microspheres were successfully synthesized by tuning the concentration of CQDs in the solutions with glutathione as a template. The formation process of the uniform C/CdS microspheres was investigated by time-dependent experiments. The C/CdS exhibits obviously enhanced photocatalytic activity toward degradation of RhB under the solar-simulated light irradiation. In addition, a higher and more stable photocurrent was generated at the C/CdS electrode under visible light irradiation. The significant enhancement in the carrier density and annihilation of fluorescence after incorporation of CQDs into the CdS microspheres further confirm the efficient charge separation and transportation in the composites. The CQDs in the composites can efficiently trap electrons, thus hindering the recombination of photo-generated electrons and holes.