Photocatalytic hydrogen production of the CdS/TiO₂-WO₃ ternary hybrid under visible light irradiation

An attractive and effective method for converting solar energy into clean and renewable hydrogen energy is photocatalytic water splitting over semiconductors. The study aimed at utilizing organic sacrificial agents in water, modeled by formic acid, in combination with visible light driven photocatalysts to produce hydrogen with high efficiencies. The photocatalytic hydrogen production of cadmium sulfide (CdS)/titanate nanotubes (TNTs) binary hybrid with specific CdS content was investigated. After visible light irradiation for 3 h, the hydrogen production rate of 25 wt% CdS/TNT achieved 179.35 μmol·h⁻¹. Thanks to the two-step process, CdS/TNTs-WO₃ ternary hybrid can better promote the efficiency of water splitting compared with CdS/TNTs binary hybrid. The hydrogen production of 25 wt% CdS/TNTs-WO₃ achieved 212.68 μmol·h⁻¹, under the same condition. Coating of platinum metal onto the WO₃ could further promote the reaction. Results showed that 0.2 g 0.1 wt% Pt/WO₃ + 0.2 g 25 wt% CdS/TNTs had the best hydrogen production rate of 428.43 μmol·h⁻¹. The resultant materials were well characterized by high-resolution transmission electron microscope, X-ray diffraction, scanning electron microscopy, and UV-Vis spectra.