Ligand-controlled photocatalysis of sulfur dots/MoS2 nanocomposite for degradation of dye and antibiotic

Manipulating surface organic ligands has emerged as a useful strategy to enhance the efficiency of catalysis. Here, a novel photocatalyst of S dots/MoS2 nanocomposite with the ligand of polyethylene glycol 400 (PEG) or poly (sodium-p-styrenesulfonate) (PSS) was synthesized. Compared to pure S dots and MoS2, S dots/MoS2 nanocomposite modified with PEG inhibited the photocatalytic activity, while the S dots/MoS2 nanocomposite modified with PSS exhibited improved photocatalysis efficiency. And degradation efficiency of S dots/MoS2-PSS was achieved to be 88% (120 min) and 83% (90 min) for degradation of Rhodamine B (RhB) and Doxycycline hydrochloride (DOX), respectively. It was found that the ligand mainly affect the energy gap and the conduction band potential of the photocatalyst, leading to different photocatalysis activity. When S dots-PSS and MoS2 were combined, the photoelectric conversion performance was enhanced and the recombine of the photogenerated carriers were depressed. And the low conduction band potential of photogenerated electron facilitate to produce of •OH and •O2- radical. This study provides a new photocatalysts and also give a reference on the ligands option of designing efficient photocatalysts.