Nanohybrid MoS2-PANI-CdS photocatalyst for hydrogen evolution from water

A ternary nanohybrid material, MoS2-PANI(polyaniline)-CdS, exhibits enhanced photocatalytic activity for hydrogen generation from water compared to single phase CdS, MoS2-CdS and PANI-CdS composites. The photocatalytic activity increases further when palladium is used as co-catalyst. The modified CdS composite catalyst is found to be stable for repeated cycles of photocatalytic experiments. Increased visible light absorption is seen when CdS is modified with PANI and MoS2 having a layered structure. Detailed characterization suggests that CdS, PANI and MoS2 exist as an intimate blend in the composite. Time resolved fluorescence studies show an increased lifetime for the photogenerated charge carriers in MoS2-PANI-CdS composite. Photocurrent measurements show relatively higher current output for the MoS2-PANI-CdS sample compared to CdS and other binary composites. The increased photocatalytic activity of the modified CdS catalyst is attributed to the increased visible light absorption, increased photoresponse and increased lifetime of the photogenerated charge carriers promoted by both PANI and MoS2. In the presence of Pd co-catalyst, interfacial transfer of electrons from the catalyst to Pd occurs, which enhances the separation of charge carriers and provides active sites for hydrogen evolution. Present study provides insights for improving the photocatalytic activity of CdS photocatalyst.