Effect of cobalt doping on the photocatalytic performance of AgInS2 for organic pollutant degradation and hydrogen production

In this work, AgInS2 (AIS) and cobalt (Co) doped AgInS2 (Co-AIS) are prepared by low-temperature liquid phase method using thioglycolic acid (TGA) as the stabilizing agent. The crystal structure, surface elements, binding energy, particle morphology, and optical properties of AIS and Co-AIS are analyzed by XRD, XPS, SEM, TEM, UV-Vis-DRS, and PL. Rhodamine B (RhB) and 4-nitrophenol (4-NP) are used as the model pollutants for evaluating the photocatalytic activities of AIS and Co-AIS. The optimal doping ratio of CoːIn is found to be 10.7:6.3. And, under this optimal ratio, Co-AIS can degrade 95 % of RhB in 1.5 h or 76 % of 4-NP in 2.5 h, respectively. The photocatalytic mechanism is proposed based on the active species trapping experiment, EPR technique, optical properties characterization, and the flat-band potential determination. Moreover, the photocatalytic water splitting performance of Co-AISs with or without the modification of the multi-walled carbon nanotubes (MWCNTs) are investigated, and remarkable hydrogen production is achieved. This research will open a new gateway to synthesizing AgInS2-based materials and exploring their photocatalytic activities.