Photoelectrochemical hydrogen generation on TiO2 nanotube arrays sensitized with CdS@Sb2S3 core shell particles

In this work, we propose the sensitization of TiO2 nanotube arrays with CdS and Sb2S3 (TNTs-CdS@Sb2S3), in order to improve the visible light absorbance, and the photoelectrochemical performance as photoanodes in photoelectrochemical cells for hydrogen production. It is the first time that these materials have been synthesized by an electrochemical/thermal/chemical method. TNTs-CdS@Sb2S3 were characterized by X-Ray Diffraction, UV-Vis diffuse reflectance spectroscopy, scanning electron microscopy and energy-dispersive X-ray spectroscopy. The diffuse reflectance spectrum obtained for TNTs-CdS@Sb2S3 confirms a total coverage of the firstly electrodeposited Cd particles by Sb forming a core@shell type structure. The photoelectrochemical behavior of the TNTs-CdS@Sb2S3 photoelectrodes and their hydrogen production capacity, were evaluated in a homemade H-type photoelectrochemical cell using a sulfide-free electrolyte. By performing gas chromatography experiments, it was determined a higher hydrogen production using the TNTs-CdS@Sb2S3 photoelectrode (10.23 μmol h−1), being 1.5 and 4.5 times higher than that reached for the TNTs-CdS and TNTs-Sb2S3 photoelectrodes, respectively. Additionally, the chalcogenide core@shell structure shows better photo-stability and photocurrent response than that of each of the components separately.