Highly efficient photocatalytic hydrogen generation of PtPd nanoframe/2D-CdS: Shape-controlled preparation and property modulation

This work focuses on the structure design of Pt-based alloys, and their influences on 2D-CdS semiconductor photocatalyst in hydrogen (H ₂ ) generation reaction from water-splitting under visible light, using traditional experimental techniques and DFT calculations as Pd concave nanocube (Pd CNCs) as a template, PtPd _x alloy with cuboctahedron core-shell structure (PtPd _x NPs) and cuboctahedron nanoframe (PtPd _y NFs) were successfully synthesized via wet chemical routes. The structure of Pt-based alloys was certified by XRD, HRTEM, XPS, and ICP. The Pt-based co-catalysts were photo-deposited on 2D-CdS in an aqueous solution of (NH ₄) ₂SO ₃ while the reaction for photo-generating of H ₂ occurred. The obtained photocatalysts show excellent activity towards hydrogen generation, i.e., in ascending order, Pd CNCs/2D-CdS (46.1 mmol/h/g) < PtPd _1.8 NPs/2D-CdS (55.4 mmol/h/g) < PtPd _0.2 NFs/2D-CdS (71.7 mmol/h/g, QE=61.46%, λ=420 nm). Photoelectrochemical tests, ESR, and work function s results indicate that PtPd _0.2 NFs have excellent photoelectrochemical performance, the longest lifetime of electrons, and the highest work function, respectively. Moreover, DFT calculations unveil that PtPd _0.2 has the largest surface energy and the lowest activation energy ΔG _H* which results in the fast charge transfer rate at the PtPd _0.2/2D-CdS interface. This work offers a novel thought into the structural design of Pt-based co-catalysts applied in photocatalytic hydrogen generation from water-splitting.