Pt4Pd–MgF2/2d-CdS: Dual-site enhanced photocatalytic water splitting for hydrogen evolution

Cadmium sulfide (CdS), as visible-light driven photocatalysts for water splitting to produce hydrogen, has been extensively investigated. However, its practical application is hindered by the rapid recombination of photogenerated carriers. To address this limitation, Pt 4 Pd/MgF 2 /CdS was developed in this study. The structure of the synthesized 1.5 %-Pt 4 Pd/MgF 2 /CdS was characterized by XRD, HRTEM, and XPS, the results showed that both MgF 2 and Pt 4 Pd uniformly distributed on the surface of 2D-CdS. Then, the photocatalytic performance of Pt 4 Pd/MgF 2 /CdS was tested, and the results demonstrated that 1.5 %-Pt 4 Pd/MgF 2 /CdS exhibits high activity and stability, with a hydrogen production rate of 75 mmol/h/g. Based on measurements results (UV–Vis/PL/ESR/work function), we propose that the increase of photocatalytic efficiency atributed to: 1) MgF 2 inhibits the photocorrosion of CdS without affecting light absorption; 2) the abundant Lewis acid sites on the MgF 2 surface facilitate the transfer of conduction band electrons from 2D-CdS; 3) the loading of Pt 4 Pd alloy onto the CdS surface forms a Schottky barrier, which promotes the separation of photogenerated charge carriers.