Edge engineering of platinum nanoparticles via porphyrin-based ultrathin 2D metal–organic frameworks for enhanced photocatalytic hydrogen generation.

A bottom-up method for the preparation of platinum nanoparticles (PtNPs)-decorated two-dimensional (2D) metal–organic framework (MOF) nanocomposites was developed with a maximum water decomposition rate of 3348 μmol g-1h−1 and sufficient stability. [Display omitted] • The Zr-TCPP(Pd) and Zr-TCPP ultrathin nanosheets were successfully synthesized. • The nanosheets modified with Pt NPs show excellent photocatalytic performance. • DFT revealed the importance of Pd-doping position in Pt 79 NPs on the activity. Edge-doping engineering in metal nanoparticles (MNPs) is always hard to achieve due to the high surface energy of the hybrid MNPs, while porphyrin-based ultrathin two-dimensional (2D) metal–organic framework (MOF) is demonstrated the positive role in stabilize this structure. Herein, a bottom-up method was developed to prepare platinum nanoparticles (PtNPs)-decorated 2D MOF nanosheets, where a porphyrin ligand of Pd-metalized tetrakis(4-carboxyphenyl)porphyrin (PdTCPP) was applied to synthesize ultrathin MOF nanosheets as Zr-TCPP(Pd) in high yield. Attributing to the high superficial area of ultrathin Zr-TCPP(Pd) nanosheets, Pt NPs can well anchor uniformly with small nanoparticle size to obtain 2% Pt/Zr-TCPP(Pd) hybrid nanosheets, which showed a higher photocatalytic hydrogen production rate of 3348 μmol g-1h−1. This is attributed to the coordination between Zr4+ and C = O of PVP, which promotes the contact between PtNPs and Zr-TCPP(Pd) nanosheets. As a result, the long-life electrons of PdTCPP photosensitizers are rapidly transferred to the electron capture center PtNPs, and the photoelectron-hole recombination is effectively inhibited. The apparent quantum efficiency of 2% Pt/Zr-TCPP(Pd) reaches up to 1.56% at 420 nm. The density functional theory (DFT) calculations revealed the Pd-doped position in Pt 79 nanoparticle is important that the Pt 78 Pd surf. model (Pd atom was doped on the surface of Pt nanoparticle) showed the highest activity with abundant exposed active region. [ABSTRACT FROM AUTHOR]