Synthesis of CdS-Vo-TiO2 heterojunction composite catalyst by photodeposition of Pt–Pd nanoparticles and their photocatalytic reaction properties studies

Photocatalytic water splitting for hydrogen production and the degradation of organic pollutants are regarded as promising strategies to address the current energy crisis and environmental issues. As a wide-bandgap metal oxide, TiO 2 is characterized by low catalytic activity and a narrow range of light absorption when used alone, whereas its combination with narrow-bandgap semiconductors has been shown to lead to a significant enhancement in catalytic performance. In this study, CdS–TiO 2 composites were synthesized via a ball-milling method, after which Pt–Pd nanoparticles were deposited by photodeposition. The noble metals were found to interact with CdS and TiO 2 respectively, while a synergistic catalytic effect between Pd and Pt was also observed. The photocatalytic efficiency was further extended by the formation of CdS–TiO 2 heterojunctions, resulting in a significantly enhanced hydrogen production rate of 4656.99 μmol h −1  g cat −1 in the ternary system. Moreover, the composite demonstrated significantly enhanced performance in the photocatalytic reduction of 4-NP, The Pt–Pd NPs/CdS-Vo-TiO 2 photocatalyst achieved a 95.2 % conversion rate for 4-NP within 2 min, also demonstrating high photocatalytic activity.