Single Pt Atom with Highly Vacant d-Orbital for Accelerating Photocatalytic H₂ Evolution

Abstract

Modulating the electronic structure of cocatalysts is critical for designing active sites toward efficient photocatalytic H 2 evolution. Here, we report an electronic modulation in atomically dispersed Pt as highly efficient H 2 -evolution sites on graphitic carbon nitride (g-C 3 N 4 ) nanosheets. Synchrotron radiation X-ray spectroscopic results confirm the singly dispersed Pt atoms anchored on g-C 3 N 4 via forming "Pt 1 −N 4 " moiety, where the strong interaction of Pt with supports leads to the redistribution of Pt valence electrons with the highly vacant 5d orbital. Mechanistic investigations reveal that the immobilization of Pt single atoms with electron-deficient 5d orbitals on g-C 3 N 4 nanosheets not only facilitate the separation of electron−holes pair but also optimize the water reduction kinetics on the surface. As a result, the Pt single atoms photocatalyst achieves a high intrinsic activity with turnover frequency of 250 h −1 , about 13 times higher than the 19.5 h −1 of its nanocrystal counterpart.

Recent Progress in Single‐Atom Catalysts for Photocatalytic Water Splitting

“…Cao et al anchored successfully single Pt atoms over g-C 3 N 4 (Pt-SA/CN), which displayed the H 2 generation rate of 42.1 μmol h À1 and TOF of 250 h À1 under light irradiation. [168] The strong interaction between isolated Pt atoms and g-C 3 N 4 can cause Pt valence electrons to be redistributed to form more highly unoccupied 5d orbitals and accelerate photoexcited charge transfer, thus enhancing photocatalytic activity for H 2 evolution. It can be observed that no obvious Pt clusters and nanocrystals were produced in the Pt-SA/CN photocatalyst, where atomic Pt was uniformly dispersed (Figures 11a,b).…”

“…a-f ) Reproduced with permission. [168] Copyright 2018, American Chemical Society. g,h) Reproduced with permission.…”

Versatile Applications of Metal Single‐Atom @ 2D Material Nanoplatforms

“…b) DRIFTS of CO adsorbed on Pt‐SA/CN after being purged with Ar gas for different time. Reproduced with permission . Copyright 2018, American Chemical Society.…”

Artificial Photosynthesis with Polymeric Carbon Nitride: When Meeting Metal Nanoparticles, Single Atoms, and Molecular Complexes

“…What calls for special attention is that the atomic and electronic structure of the single‐atom metal will change with downsizing from nanocrystals to single atoms. Cao et al employed X‐ray spectroscopy characterization and DOS calculation to deeply investigate the electronic modulation of Pt single atom in PCN for the improved photocatalytic activity . Through an in situ photodeposition process, Pt single atoms were coordinated with the N atoms of PCN in the form of “Pt 1 –N 4 ” moiety, where the strong interaction between Pt atoms and ligands resulted in the redistribution of Pt valence electrons, forming a highly vacant of 5d orbitals.…”