High photoelectrochemical performance of reduced graphene oxide wrapped, CdS functionalized, TiO2 multi-leg nanotubes.

Absorption of visible light and separation of photogenerated charges are two primary pathways to improve the photocurrent performance of semiconductor photoelectrodes. Here, we present a unique design of tricomponent photocatalyst comprising of TiO2 multileg nanotubes (MLNTs), reduced graphene oxide (rGO) and CdS nanoparticles. The tricomponent photocatalyst shows a significant red-shift in the optical absorption (~ 2.2 eV) compared to that of bare TiO2 MLNTs (~ 3.2 eV).The availability of the both inner and outer surfaces areas of MLNTs, visible light absorption of CdS, and charge separating behavior of reduced graphene oxide layers contribute coherently to yield a photocurrent density of ~11 mA/cm2 @ 0 V vs. Ag/Cl (100 mW/cm2, AM 1.5 G). Such a high PEC performance from TiO2/rGO/CdS photoelectrode system has been analyzed using diffused reflectance (DRS) and electrochemical impedance (EIS) spectroscopy techniques. The efficient generation of charge carriers under light irradiation and easy separation because of favourable band alignment are attributed to the high photoelectrochemical current density in these tricomponent photocatalyst system.